# CommandSection

title: INTEGRATION WITH UDEV
content:
<b>usb_modeswitch_dispatcher</b> is not a standalone command intended for direct user execution. It is a critical part of the <b>usb-modeswitch</b> package's automatic mode-switching capabilities. Its execution is managed by <b>udev</b> rules, which are typically defined in files like <i>/lib/udev/rules.d/40-usb_modeswitch.rules</i>. These rules monitor USB device hotplug events and invoke the dispatcher script when a known multi-mode device is detected.


title: PURPOSE OF DISPATCHER
content:
While <b>usb_modeswitch</b> performs the actual device command sending, the dispatcher's role is to act as an intelligent intermediary. It reads the device's Vendor ID and Product ID (provided by <b>udev</b>), looks up the correct switching command in the <b>usb_modeswitch</b> configuration database, and then executes <b>usb_modeswitch</b> with the specific parameters for that device. This abstraction simplifies the <b>udev</b> rules and centralizes the logic for device identification and parameter selection.


title: HISTORY
content:
<b>usb_modeswitch_dispatcher</b> emerged as a necessary component to automate the functionality of <b>usb_modeswitch</b>, which was initially designed for manual invocation. As the number of multi-mode USB devices (especially 3G/4G modems) proliferated, manually running <b>usb_modeswitch</b> for each connection became impractical. The dispatcher script was developed to integrate seamlessly with the Linux <b>udev</b> system, allowing for automatic detection and switching of devices upon connection. This evolution significantly improved the user experience, transforming what was once a manual troubleshooting step into a plug-and-play operation for a wide range of mobile broadband devices, solidifying <b>usb-modeswitch</b>'s role in network connectivity management on Linux.


title: PARAMETERS
content:
<b><i>&lt;device&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The path to the USB printer device node (e.g., <i>/dev/usb/lp0</i>, <i>/dev/usb/lp1</i>).<br><br><b><b>-r</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Output the raw IEEE 1284 Device ID string without parsing it into key-value pairs.<br><br><b><b>-c</b> <i>&lt;n&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the printer configuration number. Defaults to 1 if not provided.<br><br><b><b>-i</b> <i>&lt;n&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the printer interface number. Defaults to 0 if not provided.<br><br><b><b>-q</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable quiet mode. Suppresses most error messages, providing cleaner output.<br><br><b><b>-u</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display usage information for the command.<br><br><b><b>-v</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display version information for the command.<br><br>


title: DESCRIPTION
content:
The <b>usb_printerid</b> command is a specialized utility used to retrieve the IEEE 1284 Device ID string from a connected USB printer. This unique string provides crucial identification information about the printer, including its manufacturer, model, and supported command sets (e.g., PCL, PostScript).<br><br>Printer drivers and print spooling systems (like CUPS) often utilize this ID to automatically detect, configure, and apply the correct driver for a specific printer, ensuring proper functionality and access to all features. By specifying the device path (e.g., <i>/dev/usb/lp0</i>), <b>usb_printerid</b> communicates directly with the printer to extract this valuable data, making it an essential tool for printer setup, troubleshooting, and low-level diagnostics on Linux systems.


title: CAVEATS
content:
<i><b>1. Permissions:</b> Requires appropriate permissions to access the USB device node (typically root privileges or membership in the 'lp' or 'usb' group).<br><b>2. ID Support:</b> The command only works for USB printers that support querying for the IEEE 1284 Device ID. Some older or very simple printers might not.<br><b>3. Device Path:</b> The device path (e.g., /dev/usb/lp0) might vary depending on the system and the order of USB device detection.</i>


title: IEEE 1284 DEVICE ID STRUCTURE
content:
The IEEE 1284 Device ID string is a semicolon-separated list of key-value pairs. Common keys include:<br><i><b>MANUFACTURER</b></i>: The printer's manufacturer.<br><i><b>MODEL</b></i>: The printer's model name.<br><i><b>COMMAND SET</b></i>: The printer's supported command languages (e.g., PCL, PostScript, ESC/P, GDI).<br><i><b>CLASS</b></i>, <i><b>DESCRIPTION</b></i>, <i><b>COMMENT</b></i>: Additional descriptive information.<br>This structured data is crucial for automatic driver matching and printer configuration.


title: HISTORY
content:
<b>usb_printerid</b> is part of the broader collection of utilities supporting USB device interaction on Linux, often bundled with packages like <i>usbutils</i> or printer-specific helper tools. Its development coincided with the increasing adoption of USB as the primary printer interface, providing a standardized way for the operating system and print drivers to identify and configure printers based on their inherent characteristics, rather than relying solely on vendor-specific drivers.


title: SYNOPSIS
content:
<i>usbip</i> [OPTIONS] &lt;subcommand&gt; [ARGS]<br><br>Common subcommands and their usage:<br><b>usbip list</b> [<b>-l</b> | <b>-r</b> &lt;host&gt; [<b>--tcp-port</b>=&lt;port&gt;]]<br><b>usbip bind</b> <b>-b</b> &lt;busid&gt;<br><b>usbip unbind</b> <b>-b</b> &lt;busid&gt;<br><b>usbip attach</b> <b>-h</b> &lt;host&gt; <b>-b</b> &lt;busid&gt; [<b>--tcp-port</b>=&lt;port&gt;]<br><b>usbip detach</b> <b>-p</b> &lt;port&gt;<br><b>usbip port</b><br><b>usbip version</b><br><b>usbip help</b>


title: PARAMETERS
content:
<b><b>-l</b>, <b>--local</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Used with <i>usbip list</i> to display local USB devices available for binding.<br><br><b><b>-r</b> &lt;host&gt;, <b>--remote</b>=&lt;host&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Used with <i>usbip list</i> to display USB devices exported by a specified remote host (by hostname or IP address).<br><br><b><b>-b</b> &lt;busid&gt;, <b>--busid</b>=&lt;busid&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the bus ID of a USB device, e.g., '1-1' or '2-2.1'. Required for <i>bind</i>, <i>unbind</i>, and <i>attach</i> operations.<br><br><b><b>-h</b> &lt;host&gt;, <b>--host</b>=&lt;host&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the hostname or IP address of the remote server. Required for <i>usbip attach</i>.<br><br><b><b>-p</b> &lt;port&gt;, <b>--port</b>=&lt;port&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the port ID of a virtual host controller to which a device is attached. Required for <i>usbip detach</i>.<br><br><b><b>--tcp-port</b>=&lt;port&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Allows specifying a custom TCP port number for usbip communication, overriding the default port 3240. Used with <i>list -r</i> and <i>attach</i>.<br><br><b><b>-D</b>, <b>--debug</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables verbose debug output to stderr, useful for troubleshooting.<br><br><b><b>--dmesg</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Prints kernel messages related to usbip operations, often providing more context on device interactions.<br><br><b><b>-v</b>, <b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays the current version information of the usbip utility.<br><br>


title: DESCRIPTION
content:
<i>usbip</i> is a Linux command-line tool that enables the sharing of USB devices over an IP network. It allows a client machine to use a USB device physically connected to a remote server as if it were directly attached locally. This functionality is achieved by creating a virtual USB host controller on the client and tunneling USB requests across the network. It's particularly useful for virtual machine environments, remote development setups, or when needing to share specialized USB hardware without physical proximity.<br><br>The process generally involves two main steps: first, on the server, the desired USB device is bound to the <i>usbip-host</i> kernel driver, making it available for network export. Second, on the client, the remote device is attached to a local virtual host controller, specifically the <i>vhci-hcd</i> driver, which then presents it as a local USB device to the operating system.


title: CAVEATS
content:
<b>Kernel Modules:</b> Requires specific kernel modules (<i>usbip-core</i>, <i>usbip-host</i>, <i>vhci-hcd</i>) to be loaded on both server and client.<br><b>Performance:</b> Network latency and bandwidth directly impact performance, especially for high-throughput devices like storage or webcams.<br><b>Compatibility:</b> Not all USB devices work perfectly. Complex devices or those with strict timing requirements may experience issues or fail to function.<br><b>Security:</b> Exposing USB devices over the network can introduce security risks if not properly secured with firewalls or VPNs.<br><b>Single Client:</b> Only one client can attach a specific USB device at a time.


title: CLIENT-SERVER MODEL
content:
<i>usbip</i> operates using a client-server model. On the server side, the machine with the physical USB device uses <i>usbip bind</i> (or the <i>usbipd</i> daemon) to export the device, making it available over the network. On the client side, <i>usbip attach</i> is used to connect to the remote device, which then appears as a locally attached USB device to the client's operating system via a virtual host controller.


title: KERNEL MODULES EXPLAINED
content:
The functionality of <i>usbip</i> relies heavily on specific Linux kernel modules:<br><b>usbip-core</b>: The core framework for USB over IP.<br><b>usbip-host</b>: Loaded on the server, this module makes physical USB devices exportable over the network.<br><b>vhci-hcd</b> (Virtual Host Controller Interface Host Controller Driver): Loaded on the client, this module creates a virtual USB host controller that allows remote USB devices to be attached and appear as local devices.


title: HISTORY
content:
The <i>usbip</i> project emerged from efforts to provide a flexible framework for network-attached USB devices within the Linux ecosystem. It originated from the Linux Foundation's Virtual USB project and has since been integrated into the Linux kernel and user-space tools. Its development has focused on improving stability, performance, and compatibility with various USB device types over time, making it a robust solution for remote USB access.


title: PARAMETERS
content:
<b>-c, --comment COMMENT</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the GECOS field (full name, phone number, etc.) for the new user.<br><br><b>-d, --home-dir HOME_DIR</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the user's home directory. If not specified, it defaults based on <i>/etc/login.defs</i>.<br><br><b>-e, --expiredate EXPIRE_DATE</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the account expiration date in YYYY-MM-DD format.<br><br><b>-f, --inactive INACTIVE</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the number of days after a password expires until the account is permanently disabled. 0 means disable immediately, -1 means never.<br><br><b>-g, --gid GROUP</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the primary group name or GID for the new user.<br><br><b>-G, --groups GROUPS</b><br>&nbsp;&nbsp;&nbsp;&nbsp;A comma-separated list of supplementary group names or GIDs the user will be a member of.<br><br><b>-k, --skel SKEL_DIR</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies an alternative skeleton directory to copy files from instead of the default <i>/etc/skel</i>.<br><br><b>-m, --create-home</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Creates the user's home directory if it does not exist, copying files from the skeleton directory.<br><br><b>-M, --no-create-home</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Prevents the creation of the user's home directory, even if <i>/etc/login.defs</i> or <i>/etc/default/useradd</i> specifies it.<br><br><b>-N, --no-user-group</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Does not create a new group with the same name as the user's login name. The user's primary group must be specified with <i>-g</i>.<br><br><b>-o, --non-unique</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Allows creation of a user with a non-unique (duplicate) User ID (UID).<br><br><b>-p, --password PASSWORD</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies an encrypted password for the new user. <i>(Highly discouraged for security reasons; use <b>passwd</b> instead.)</i><br><br><b>-r, --system</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Creates a system account. System UIDs are typically low and these accounts often do not have a home directory.<br><br><b>-s, --shell SHELL</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the user's login shell. If not specified, the system default is used (e.g., <i>/bin/bash</i> or <i>/bin/sh</i>).<br><br><b>-u, --uid UID</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the User ID (UID) for the new user. If not specified, the next available non-system UID is chosen.<br><br><b>-U, --user-group</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces creation of a new group with the same name as the user's login name. This is the default behavior on most systems.<br><br><b>-D, --defaults</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Used without a LOGIN argument, this option displays the current default values for new user accounts. With other options, it modifies these defaults.<br><br>


title: DESCRIPTION
content:
<b>useradd</b> is a fundamental low-level utility on Linux systems used to create new user accounts. It directly modifies system account files such as <i>/etc/passwd</i>, <i>/etc/shadow</i>, <i>/etc/group</i>, and <i>/etc/gshadow</i> to register the new user's information. When creating a user, it can optionally create a home directory, copy skeleton files (from <i>/etc/skel</i>) into it, assign a primary group, add to supplementary groups, define a login shell, and set other account attributes like UID, GID, and expiration date.<br><br>Unlike some higher-level tools like <b>adduser</b> (often found on Debian/Ubuntu), <b>useradd</b> does not typically prompt for a password or other details interactively. A password must be set separately using the <b>passwd</b> command after the account creation. It's an essential tool for system administrators managing users directly from the command line or through scripts, providing granular control over user account properties.


title: CAVEATS
content:
<b>useradd</b> does not set a password for the new account by default. You must use the <b>passwd</b> command immediately after creating the user to set their password.<br><br>Using the <i>-p</i> option to provide an encrypted password on the command line is a security risk as the password might be visible in process listings (e.g., <i>ps aux</i>) and shell history. It is highly recommended to use <b>passwd</b> for secure password setting.<br><br>The default behavior of <b>useradd</b> can vary between Linux distributions and is heavily influenced by settings in <i>/etc/login.defs</i> and <i>/etc/default/useradd</i>.<br><br>In some distributions (e.g., Debian/Ubuntu), <b>adduser</b> is often preferred over <b>useradd</b> for interactive user creation as it handles more steps automatically, including password prompting and home directory creation, making it more user-friendly for manual operations.


title: DEFAULT CONFIGURATION FILES
content:
<b>useradd</b> retrieves its default values (like UID/GID range, home directory parent, shell, etc.) from two primary configuration files: <i>/etc/login.defs</i> and <i>/etc/default/useradd</i>. <i>/etc/login.defs</i> contains system-wide configuration settings for login, password, and user/group creation, while <i>/etc/default/useradd</i> specifically holds defaults for the <b>useradd</b> command itself (e.g., HOME, SHELL, SKEL, EXPIRE).


title: SKELETON DIRECTORY
content:
By default, when a home directory is created (<i>-m</i> option), <b>useradd</b> copies the contents of the <i>/etc/skel</i> directory into the new user's home directory. This allows administrators to provide default configuration files, templates, or welcome messages for new users, ensuring a consistent initial environment. Examples of files often found in <i>/etc/skel</i> include <i>.bashrc</i>, <i>.profile</i>, and <i>.vimrc</i>.


title: HISTORY
content:
The <b>useradd</b> command is a standard utility on Unix-like operating systems, including Linux, and has been a core component of user management toolsets for decades. Its origins lie in the early Unix systems, where similar utilities were needed to manage user accounts by modifying system flat files. In Linux, it is typically part of the <i>shadow-utils</i> package (or <i>passwd</i> package on some systems), which provides tools for managing user and group accounts and their shadow passwords. While its core functionality remains consistent, its implementation and default behaviors have evolved with Linux distributions, adapting to security best practices and system conventions.


title: SYNOPSIS
content:
<b>userdbctl</b> [<i>OPTION...</i>] <i>COMMAND</i> [<i>ARG...</i>]<br><br><b>Commands:</b><br> &nbsp; <b>userdbctl list</b><br> &nbsp; <b>userdbctl show</b> <i>&lt;user&gt;</i><br> &nbsp; <b>userdbctl add</b> <i>&lt;user&gt;</i> [<i>attribute=value...</i>]<br> &nbsp; <b>userdbctl del</b> <i>&lt;user&gt;</i><br> &nbsp; <b>userdbctl modify</b> <i>&lt;user&gt;</i> [<i>attribute=value...</i>]<br> &nbsp; <b>userdbctl passwd</b> <i>&lt;user&gt;</i>


title: PARAMETERS
content:
<b><b>-h</b>, <b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a help message and exits.<br><br><b><b>-p</b>, <b>--plain-password</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;When used with 'add' or 'modify' commands, treats the 'password' attribute value as plain text to be hashed by <i>userdbctl</i> before storage. Without this option, the password value is expected to be already hashed.<br><br><b><b>-S</b>, <b>--stdin-password</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Used with the 'passwd' command to read the new password from standard input (stdin) instead of prompting interactively. This is useful for scripting.<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables verbose output, providing more detailed information about the operations being performed.<br><br><b><b>-s</b> <i>&lt;path&gt;</i>, <b>--socket</b> <i>&lt;path&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the path to the SSSD userdb daemon's Unix socket. The default path is typically <i>/var/lib/sssd/pipes/userdb</i>.<br><br><b><b>list</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Lists all users currently present in the SSSD userdb.<br><br><b><b>show</b> <i>&lt;user&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays detailed information for the specified user, including their UID, GID, GECOS, home directory, shell, and other attributes.<br><br><b><b>add</b> <i>&lt;user&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Adds a new user with the given username to the SSSD userdb. Requires specifying user attributes like UID, GID, etc.<br><br><b><b>del</b> <i>&lt;user&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Deletes the specified user from the SSSD userdb.<br><br><b><b>modify</b> <i>&lt;user&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Modifies the attributes of an existing user in the SSSD userdb. Accepts the same attribute=value pairs as the 'add' command.<br><br><b><b>passwd</b> <i>&lt;user&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Changes the password for the specified user. If <b>--stdin-password</b> is not used, it will prompt for the new password interactively.<br><br>


title: DESCRIPTION
content:
<i>userdbctl</i> is a command-line utility used to manage users within SSSD's local user database, known as <i>userdb</i>. This database is primarily utilized by the <i>nss-userdb</i> SSSD module to provide local user and group information to the system's Name Service Switch (NSS). The command allows administrators to perform various operations, including adding new users, deleting existing ones, modifying user attributes, listing all configured users, displaying details for a specific user, and setting or changing user passwords. It communicates directly with the <i>sssd-userdb</i> daemon via a Unix socket, enabling robust local account management independent of external identity providers.


title: CAVEATS
content:
<i>userdbctl</i> requires the <i>sssd-userdb</i> daemon to be running and properly configured in <i>sssd.conf</i> to manage users. The command directly manipulates SSSD's internal database, so direct editing of SSSD's database files is not recommended. When setting passwords, be cautious about providing plaintext passwords directly on the command line, as they might be visible in process listings; prefer using <b>--stdin-password</b> or providing already hashed passwords.


title: USER ATTRIBUTES FOR ADD/MODIFY COMMANDS
content:
When using the <b>add</b> or <b>modify</b> commands, specific user attributes can be provided as <i>attribute=value</i> pairs:<br> &nbsp; <i>uid=&lt;integer&gt;</i>: The user's numeric User ID.<br> &nbsp; <i>gid=&lt;integer&gt;</i>: The user's primary numeric Group ID.<br> &nbsp; <i>gecos="&lt;string&gt;"</i>: The GECOS field (full name or comment). Must be quoted if it contains spaces.<br> &nbsp; <i>home="&lt;path&gt;"</i>: The user's home directory path. Must be quoted if it contains spaces.<br> &nbsp; <i>shell="&lt;path&gt;"</i>: The user's default login shell path. Must be quoted if it contains spaces.<br> &nbsp; <i>password="&lt;hash_or_plain_text&gt;"</i>: The user's password. If <b>--plain-password</b> is used, provide it as cleartext; otherwise, provide a pre-hashed password string (e.g., in crypt(3) format).


title: FILES
content:
<i>/var/lib/sssd/pipes/userdb</i>: This is the default path to the Unix socket used by <i>userdbctl</i> to communicate with the <i>sssd-userdb</i> daemon.


title: HISTORY
content:
<i>userdbctl</i> is part of the SSSD (System Security Services Daemon) project, specifically designed to support the <i>nss-userdb</i> module. The <i>nss-userdb</i> module was introduced to allow SSSD to provide a simple, local user and group database, separate from traditional <i>/etc/passwd</i> and <i>/etc/group</i> files, primarily for cases where a full identity management solution is not needed but local SSSD-managed accounts are desired. <i>userdbctl</i> was developed as the dedicated management interface for this local database.


title: PARAMETERS
content:
<b>-r, --remove</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Removes the user's home directory and mail spool. This option also removes the user's primary group if it contains no other members.<br><br><b>-f, --force</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces the removal of the user account, even if the user is currently logged in. Use with extreme caution as this can lead to system instability.<br><br><b>LOGIN</b><br>&nbsp;&nbsp;&nbsp;&nbsp;The username of the account to be deleted. This is a mandatory argument.<br><br>


title: DESCRIPTION
content:
The <b>userdel</b> command is used to delete a user account from the Linux system. By default, it removes the user's entry from system account files like <i>/etc/passwd</i> and <i>/etc/shadow</i>, and removes the user from any groups they are a member of. However, it does <b>not</b> remove the user's home directory or mail spool unless explicitly requested with the <i>-r</i> option. This default behavior is a safety measure to prevent accidental data loss. To successfully remove a user, it's generally best practice to ensure the user is <i>not logged in</i> and has <i>no running processes</i>. If the user's primary group has no other members after the user's deletion, the group might also be removed, depending on system configuration. The command requires root privileges to execute, as it modifies critical system files. It's a fundamental tool for system administrators to manage user lifecycles on a Linux machine, helping maintain system security and organization by removing obsolete or unauthorized accounts. Care should always be taken when using <b>userdel</b>, especially with the <i>-r</i> option, to avoid unintentional data deletion or system instability.


title: CAVEATS
content:
The user should <i>not be logged in</i> and have <i>no running processes</i> to ensure a clean deletion, unless the <i>-f</i> (force) option is used.<br>Using the <i>-r</i> option will permanently delete the user's home directory and mail spool, which is <b>irreversible</b>. Backups are recommended.<br>If the user's primary group is unique and has no other members, it might also be deleted.<br>Files and directories owned by the user outside of their home directory will <i>not</i> be affected or removed by <b>userdel</b>. These may need to be manually cleaned up.<br>Reusing a deleted user's UID (User ID) can pose security risks, as new accounts might inadvertently gain access to old files still owned by that UID.


title: AFFECTED FILES
content:
<i>/etc/passwd</i>: User account database.<br><i>/etc/shadow</i>: Secure user account information (hashed passwords).<br><i>/etc/group</i>: Group account information.<br><i>/etc/gshadow</i>: Secure group account information.<br><i>/etc/login.defs</i>: System-wide configuration for user management.


title: EXIT STATUS
content:
<b>0</b>: Success.<br><b>1</b>: Cannot update password file.<br><b>2</b>: Invalid command syntax.<br><b>6</b>: Specified user doesn't exist.<br><b>8</b>: User currently logged in.<br><b>10</b>: Cannot update group file.<br><b>12</b>: Cannot remove home directory.<br><b>14</b>: Cannot update SELinux user mapping.


title: HISTORY
content:
The <b>userdel</b> command is a fundamental part of standard Unix and Linux system administration, particularly for managing user accounts. Its evolution is closely tied to the development of the <i>shadow password suite</i> (often part of the <i>shadow-utils</i> package), which enhanced the security of user information by separating hashed passwords into a restricted file (<i>/etc/shadow</i>). Over time, its core functionality has remained consistent: safely removing user entries from system authentication files. Its design reflects best practices for system security and data integrity by requiring explicit actions (like the <i>-r</i> option) for data deletion and preventing deletion of active users by default.


title: SYNOPSIS
content:
<b>usermod</b> [<i>options</i>] <i>LOGIN</i><br>Example: <b>usermod</b> -g developers -a -G testers newuser


title: PARAMETERS
content:
<b><b>-c</b>, <b>--comment</b> <i>COMMENT</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets a new value for the user's GECOS field (e.g., full name, contact information).<br><br><b><b>-d</b>, <b>--home</b> <i>HOME_DIR</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assigns a new home directory. Use with <b>-m</b> to move the old directory's contents.<br><br><b><b>-e</b>, <b>--expiredate</b> <i>EXPIRE_DATE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the account expiration date in YYYY-MM-DD format.<br><br><b><b>-f</b>, <b>--inactive</b> <i>INACTIVE_DAYS</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the number of days after a password expires until the account is permanently disabled.<br><br><b><b>-g</b>, <b>--gid</b> <i>GROUP</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Changes the user's primary group to the specified <i>GROUP</i> (by name or GID).<br><br><b><b>-G</b>, <b>--groups</b> <i>GROUP1[,GROUP2,...]</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets new supplementary groups for the user. Use with <b>-a</b> to append to existing groups.<br><br><b><b>-a</b>, <b>--append</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Used with <b>-G</b> to add the user to new supplementary groups without removing existing ones.<br><br><b><b>-l</b>, <b>--login</b> <i>NEW_LOGIN</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Changes the user's login name. The home directory must be manually updated or moved with <b>-d</b> and <b>-m</b>.<br><br><b><b>-L</b>, <b>--lock</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Locks a user's password, effectively disabling the account.<br><br><b><b>-U</b>, <b>--unlock</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Unlocks a user's password, re-enabling the account.<br><br><b><b>-m</b>, <b>--move-home</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Moves the content of the current home directory to the new location specified by <b>-d</b>.<br><br><b><b>-s</b>, <b>--shell</b> <i>SHELL</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the user's new login shell (e.g., /bin/bash, /bin/sh).<br><br><b><b>-u</b>, <b>--uid</b> <i>UID</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assigns a new unique user ID (UID) to the user. Exercise caution, as this does not update file ownership outside the home directory.<br><br>


title: DESCRIPTION
content:
The <i>usermod</i> command is a fundamental administrative utility on Linux systems, used to modify various attributes of an existing user account. It provides a flexible way to manage user environments and permissions after an account has been created. Administrators can use <i>usermod</i> to change a user's login name, unique user ID (UID), primary group, supplementary group memberships, home directory location, login shell, password expiration date, and more. This command directly interacts with crucial system configuration files like <i>/etc/passwd</i>, <i>/etc/shadow</i>, and <i>/etc/group</i>. It is generally recommended that the target user not be logged in while performing modifications to prevent potential issues or data inconsistencies.


title: CAVEATS
content:
When using <i>usermod</i>, it's crucial to ensure the target user is <i>not</i> logged in to avoid potential system instability or data corruption. Changing a user's UID (<b>-u</b>) does <i>not</i> automatically update the ownership of files or directories outside their home directory; these often require manual updates using commands like <b>chown</b>. Changing the login name (<b>-l</b>) does not automatically rename the home directory unless used in conjunction with <b>-d</b> and <b>-m</b>. Avoid using the <b>-p</b> option to set a password directly with a plain-text value in scripts due to security risks; prefer interactive tools like <b>passwd</b>.


title: REQUIRED PRIVILEGES
content:
<i>usermod</i> requires root privileges to execute, as it modifies critical system-wide account information. Users typically invoke it using the <b>sudo</b> command.


title: SYSTEM FILES MODIFIED
content:
The command primarily modifies entries in <b>/etc/passwd</b> (user account details), <b>/etc/shadow</b> (encrypted password and expiry information), and <b>/etc/group</b> (user-to-group mappings). Understanding these files is key to advanced user management.


title: HISTORY
content:
The <i>usermod</i> command is an integral part of the <i>shadow-utils</i> package, which provides a suite of tools for managing user and group accounts on Linux and Unix-like systems. Its core functionality has remained consistent for decades, reflecting its foundational role in system administration for modifying user properties.


title: DESCRIPTION
content:
The <b>users</b> command is a straightforward utility designed to display the usernames of all users currently logged into the system. It retrieves this information by parsing the system's `utmp` file, which maintains a record of login and logout activities. Unlike more verbose commands such as <b>who</b> or <b>w</b>, <b>users</b> focuses solely on presenting a clean list of usernames.<br><br>The output typically shows all active usernames, separated by spaces, on a single line. This simplicity makes it particularly useful for quick checks, scripting, or automated tasks where only the identity of the active users is required, without needing additional details like login time, terminal, or idle status. It provides a concise snapshot of who is actively utilizing the system at the moment the command is executed.


title: CAVEATS
content:
The <b>users</b> command relies on the integrity and currency of the system's <i>utmp</i> file (commonly found at `/var/run/utmp` or `/var/log/utmp`). If this file becomes corrupted or is not properly updated due to system issues or specific session types (e.g., abnormal termination of an SSH session), the output of <b>users</b> might not be entirely accurate. It provides only a list of usernames and no further details such as login time, terminal, or idle status. For more comprehensive user information, other commands like <b>who</b> or <b>w</b> should be used.


title: HISTORY
content:
The <b>users</b> command is a fundamental and long-standing utility in Unix-like operating systems, serving its primary purpose of listing logged-in users consistently for decades. It's often found as part of the traditional `login` or `who` utilities package. In contemporary Linux distributions, <b>users</b> is typically included as part of the GNU `coreutils` package, which ensures its widespread availability and largely uniform behavior across different systems. Its minimalist design reflects the early Unix philosophy of creating small, focused tools that perform one task well, making them easily combinable for more complex operations.


title: PARAMETERS
content:
<b>-c, --command</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Execute a single command string and exit.</i><br><br><b>-f, --file</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Execute commands from a specified file.</i><br><br><b>-v, --variable</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Set a <I>usql</I> variable (e.g., VAR=value).</i><br><br><b>-X, --no-rc</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Do not read the start-up file (typically ~/.usqlrc).</i><br><br><b>-p, --password</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Force <I>usql</I> to prompt for a password before connecting.</i><br><br><b>-P, --no-password</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Never prompt for a password.</i><br><br><b>-h, --help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Show help message and exit.</i><br><br><b>-V, --version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Display version information and exit.</i><br><br><b>-S, --no-pager</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Disable use of a pager for command output.</i><br><br><b>-q, --quiet</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Run in quiet mode, suppressing most messages.</i><br><br><b>-E, --echo-queries</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Echo SQL queries sent to the server.</i><br><br><b>-e, --echo-commands</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Echo commands (including meta-commands) before execution.</i><br><br><b>-l, --list</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>List all available database drivers and exit.</i><br><br><b>-d, --dsn</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Specify a Data Source Name for the connection (can be repeated).</i><br><br><b>-o, --output</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Send query output to a specified file.</i><br><br><b>-H, --no-header</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Do not print column header names.</i><br><br><b>-J, --json</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Format query output as JSON.</i><br><br><b>--csv</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Format query output as CSV.</i><br><br><b>--tsv</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Format query output as TSV.</i><br><br><b>-A, --no-align</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Produce unaligned output (tab-separated by default).</i><br><br><b>-F, --field-separator</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Set the field separator for unaligned output.</i><br><br><b>-R, --record-separator</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Set the record separator for unaligned output.</i><br><br><b>-t, --tuples-only</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Show only rows of data, suppressing headers, footers, and other information.</i><br><br><b>-x, --expanded</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Enable expanded output mode (each row is printed on multiple lines).</i><br><br><b>-U, --user</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Specify the username for the connection.</i><br><br><b>-C, --color</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Force color output, even if not connected to a TTY.</i><br><br><b>-N, --no-auto-completion</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Disable auto-completion.</i><br><br><b>-m, --meter</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Display a progress meter for long-running queries.</i><br><br><b>-r, --recursive</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Recursively search for configuration files (e.g., ~/.usqlrc).</i><br><br><b>-s, --single-line</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Enter single-line mode (newline terminates SQL command).</i><br><br><b>-O, --option</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Set a <I>usql</I> option.</i><br><br><b>-i, --init-file</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Read and execute commands from a file after connecting.</i><br><br><b>-w, --write</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Write mode: print responses to stdout and exit. Useful for scripting.</i><br><br>


title: DESCRIPTION
content:
<i>usql</i> is a universal command-line interface for working with a wide range of SQL databases. Built upon Go's <I>database/sql</I> package, it offers a consistent interactive experience across various database systems like PostgreSQL, MySQL, SQLite3, SQL Server, Oracle, and many more. It provides powerful features such as auto-completion for SQL keywords and database objects, syntax highlighting, and a rich set of meta-commands (like <I>\dt</I> to list tables). <br><br><i>usql</i> aims to abstract away the specific CLI tools for each database, providing a single, unified interface for developers and DBAs. Its extensible architecture allows it to support new database drivers easily. This makes <i>usql</i> an indispensable tool for anyone who frequently interacts with different SQL databases, streamlining their workflow and enhancing productivity by reducing the need to learn multiple distinct command-line environments.


title: CAVEATS
content:
<i>usql</i> relies on Go's <I>database/sql</I> drivers. While it supports a vast array of databases, the specific functionality and stability can vary depending on the underlying driver and database system. Users might need to ensure the correct drivers are available for compilation or dynamically loaded, depending on the <I>usql</I> distribution. <br><br>Command-line DSNs can expose sensitive credentials; prefer environment variables or configuration files for production environments. Some very specific, database-CLI-native features might not be directly replicated in <I>usql</I>'s universal interface.


title: INTERACTIVE FEATURES
content:
<I>usql</I> boasts intelligent auto-completion for SQL keywords, database object names (tables, columns, views), and <I>usql</I>'s own meta-commands. It also provides syntax highlighting for queries, enhancing readability in the terminal.


title: META-COMMANDS
content:
Similar to <I>psql</I>, <I>usql</I> offers a rich set of internal commands (e.g., <I>\d</I>, <I>\l</I>, <I>\?</I>) that allow users to inspect database schema, list connections, and manage the <I>usql</I> environment without writing raw SQL.


title: CONFIGURATION
content:
<I>usql</I> supports a startup file (typically <I>~/.usqlrc</I> or <I>~/.config/usql/usqlrc</I>) where users can define aliases, set options, and execute commands automatically upon launching the client, enabling extensive customization.


title: HISTORY
content:
<I>usql</I> was created by <I>Kenneth Reitz</I> (known for <I>requests</I> and <I>pipenv</I>) in <I>2017</I>, initially envisioned as a universal client inspired by the features of <I>dbcli/pgcli</I> and <I>dbcli/mycli</I>, but written in Go. Its primary goal was to provide a consistent, feature-rich interactive SQL experience across the numerous databases supported by Go's <I>database/sql</I> ecosystem. Following its initial development, it has been actively maintained by a community, evolving to support more databases and features, becoming a popular choice for developers working with diverse data backends.


title: PARAMETERS
content:
<b><b>-f</b> <i>utmp|wtmp|btmp</i><br><b>--filetype=</b><i>utmp|wtmp|btmp</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the type of utmp file being dumped. This helps <i>utmpdump</i> correctly interpret the structure based on known variations for <i>utmp</i>, <i>wtmp</i>, or <i>btmp</i> entries.<br><br><b><b>-o</b> <i>output_file</i><br><b>--output=</b><i>output_file</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Redirects the human-readable output to the specified <i>output_file</i> instead of standard output (stdout).<br><br><b><b>-s</b><br><b>--show-structure</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays the internal structure of the utmp entry, including field offsets and sizes, which can be useful for debugging or understanding the binary format.<br><br><b><b>-v</b><br><b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provides more verbose output, potentially showing additional details about each entry or processing information.<br><br><b><i>FILE</i>...</b><br>&nbsp;&nbsp;&nbsp;&nbsp;One or more paths to utmp-like files (e.g., <i>/var/log/wtmp</i>) to be processed. If no file is specified, <i>utmpdump</i> typically defaults to <i>/var/run/utmp</i>.<br><br>


title: DESCRIPTION
content:
<i>utmpdump</i> is a utility designed to interpret and display the contents of system accounting files like <i>/var/run/utmp</i>, <i>/var/log/wtmp</i>, and <i>/var/log/btmp</i>. These files store binary records of user logins, logouts, system reboots, and other session-related information. Since these files are in a binary format, they are not directly human-readable. <i>utmpdump</i> parses these binary structures and presents the data in a formatted, plain-text output, making it easier for administrators and users to inspect login activity, session durations, and system uptime events.<br><br>It is a valuable tool for debugging login issues or performing basic system auditing by providing a detailed, field-by-field view of each utmp entry, which can be particularly useful when other high-level commands like <i>last</i> or <i>who</i> do not provide sufficient detail.


title: CAVEATS
content:
<b>Platform and Version Dependency:</b> The exact structure of <i>utmp</i>, <i>wtmp</i>, and <i>btmp</i> entries can vary slightly between different Linux distributions and even kernel versions. <i>utmpdump</i> typically handles common variations, but might misinterpret entries from highly unusual or very old systems.<br><b>Endianness:</b> While usually not an issue on modern Linux systems, differences in byte order (endianness) could theoretically affect interpretation if files are moved between systems with different architectures.<br><b>Not Universally Installed:</b> <i>utmpdump</i> is not always installed by default on all Linux distributions. It often comes as part of packages like <i>sysvinit-tools</i> or similar system utilities.


title: FILE LOCATIONS
content:
The primary files processed by <i>utmpdump</i> are:<br><b><i>/var/run/utmp</i></b>: Records current logins.<br><b><i>/var/log/wtmp</i></b>: Records all logins and logouts, system reboots, and system time changes.<br><b><i>/var/log/btmp</i></b>: Records bad (failed) login attempts. This file is not always present by default and might require specific configuration or PAM modules (e.g., <i>pam_tally2</i>).


title: PURPOSE OF UTMP-LIKE FILES
content:
These files are crucial for system accounting and security auditing. They provide a historical record of who accessed the system, from where, and for how long, as well as system events like reboots. Commands like <i>who</i>, <i>w</i>, <i>last</i>, and <i>lastb</i> all rely on these binary files, making <i>utmpdump</i> an invaluable tool for understanding the raw data these commands process when troubleshooting or conducting forensic analysis.


title: HISTORY
content:
The <i>utmpdump</i> utility's history is closely tied to the evolution of the <i>utmp</i>, <i>wtmp</i>, and <i>btmp</i> file formats themselves, which have been fundamental components of Unix-like operating systems for tracking user sessions and system events since their early days. While <i>utmpdump</i> itself isn't a universally standardized command with a prominent development history like <i>ls</i> or <i>grep</i>, various utilities performing the 'dumping' function have existed. The specific <i>utmpdump</i> implementation, often found in packages like <i>sysvinit-tools</i>, provides a convenient, standardized way to inspect these binary files, adapting to minor changes in the <i>utmp</i> structure over time. Its development has focused on providing a reliable tool for system administrators to debug and audit user activity records.


title: SYNOPSIS
content:
<b>uudecode</b> [<i>OPTION</i>]... [<i>FILE</i>]...<br><i>Decodes one or more uuencoded files. If no FILE is specified, or if FILE is '-', uudecode reads from standard input.</i>


title: PARAMETERS
content:
<b>-o <i>OUTFILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Directs the decoded output to <i>OUTFILE</i> instead of the filename specified within the uuencoded data. This is useful for renaming the file or avoiding overwriting existing files.<br><br><b>-p</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sends the decoded output to standard output (stdout) rather than creating a file. This is useful for piping the output to another command or viewing the content directly.<br><br><b><i>FILE</i>...</b><br>&nbsp;&nbsp;&nbsp;&nbsp;One or more input files containing uuencoded data. If no files are provided, or if '-' is specified, <b>uudecode</b> reads from standard input.<br><br>


title: DESCRIPTION
content:
<b>uudecode</b> is a command-line utility used to decode files that have been encoded using the uuencode utility or a similar binary-to-text encoding scheme. This encoding method, common in the early days of the internet, allowed binary data (such as executable programs, images, or archives) to be transmitted over communication channels that were primarily designed for text, like email or Usenet newsgroups.<br><br>The utility works by reading the uuencoded text, which typically starts with a "begin" line and ends with an "end" line, and reconstructing the original binary file. It also attempts to restore the original filename and file permissions embedded within the uuencoded block. While largely superseded by more robust and standardized encoding methods like MIME (Base64) for email attachments, <b>uudecode</b> remains useful for legacy systems, processing old archives, or in situations where plain text transfer is still required.


title: CAVEATS
content:
<i>Security Risk:</i> <b>uudecode</b> creates files with the name and permissions specified in the encoded data. Decoding content from untrusted sources can lead to arbitrary file creation or permission changes on your system, potentially overwriting critical files or creating executable content. Always exercise caution.<br><br><i>Input Sensitivity:</i> The decoding process is sensitive to malformed, truncated, or corrupted input. Errors in the 'begin' or 'end' lines, or in the data block itself, can cause decoding failures or result in corrupted output files.


title: FILE NAMING AND PERMISSIONS
content:
A key characteristic of <b>uudecode</b> is its ability to extract and apply the original filename and file permissions from the uuencoded header. The header typically includes a line like 'begin <i>MODE FILENAME</i>', where <i>MODE</i> specifies the file permissions in octal (e.g., 644) and <i>FILENAME</i> is the intended name of the decoded file. This feature, while convenient, also poses a security risk if decoding untrusted input.


title: STRUCTURE OF UUENCODED DATA
content:
A uuencoded block generally begins with a line similar to 'begin 644 my_file.tar.gz', followed by multiple lines of encoded data, and concludes with an 'end' line. Each data line contains 45 characters representing 45 bytes of encoded data, plus a checksum character and a newline. The encoding process translates 3 bytes of binary data into 4 ASCII characters.


title: HISTORY
content:
The <b>uudecode</b> utility, along with its encoding counterpart <b>uuencode</b>, originated in the early 1980s as part of the <b>UUCP (Unix-to-Unix Copy Program)</b> suite. It was developed to facilitate the transfer of binary files (like executables and images) across text-only communication channels, such as dial-up modems and early email systems like Usenet, long before the widespread adoption of MIME standards for email attachments. Its simplicity made it a ubiquitous method for sharing non-text data in the nascent internet era.


title: PARAMETERS
content:
<b><i>FILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the input binary file to be encoded. If this argument is omitted or specified as a hyphen (<b>-</b>), <b>uuencode</b> reads data from standard input.<br><br><b><i>NAME</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The name that the decoded file will take when processed by <b>uudecode</b>. This filename is included in the header of the encoded output, allowing the original file to be recreated with its intended name.<br><br><b><b>-m</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables <b>base64</b> encoding instead of the traditional <b>uuencode</b> format. <b>base64</b> is a more modern and widely adopted standard, especially for email attachments (MIME), producing a more compact and generally more compatible output.<br><br>


title: DESCRIPTION
content:
The <b>uuencode</b> command converts a binary file into an ASCII text format, making it suitable for transmission over communication channels that are designed primarily for text data, such as email or older newsgroup systems. <br> <br> It achieves this by taking groups of 3 bytes from the input file and representing them as 4 printable ASCII characters, ensuring that all encoded data falls within the 7-bit ASCII range, thus avoiding corruption from systems that might strip high-bit characters or interpret control characters. The output includes a header line specifying file permissions and the original filename, and a footer line 'end'. <br> <br> This mechanism was crucial in the early days of the internet for distributing software and other non-textual content reliably. Its counterpart, <b>uudecode</b>, is used to reverse this process and reconstruct the original binary file.


title: CAVEATS
content:
While historically significant, <b>uuencode</b> is largely superseded by <b>base64</b> and MIME for general-purpose binary file transfers, especially in modern email systems. The traditional <b>uuencode</b> format can sometimes face issues with line ending conversions or character set interpretations on some systems. Additionally, the encoded permissions in the header (e.g., <b>644</b>) could potentially be a security concern if decoding untrusted files, as <b>uudecode</b> will attempt to apply them.


title: OUTPUT FORMAT
content:
The output produced by <b>uuencode</b> is a block of human-readable ASCII text. It typically starts with a 'begin' line, which includes the file permissions and the filename (e.g., <i>begin 644 my_file.jpg</i>). This is followed by multiple lines of encoded data, where each line starts with a character indicating the number of encoded bytes on that line. The entire block concludes with an 'end' line on its own.


title: TRADITIONAL VS. BASE64 ENCODING
content:
The traditional <b>uuencode</b> method converts every 3 bytes of input into 4 printable ASCII characters, plus an additional character per line to denote the length of the data on that line. In contrast, <b>base64</b> encoding also converts 3 bytes into 4 characters but uses a different, more robust character set and does not include per-line length indicators; line wrapping is typically handled externally (e.g., at 76 characters) for email compatibility. The <b>-m</b> option allows <b>uuencode</b> to produce <b>base64</b> output, bridging the gap to modern standards.


title: HISTORY
content:
The <b>uuencode</b> utility originated in the early 1980s as part of Berkeley Unix (4.0BSD). It was developed to address the critical need for transmitting binary data over communication channels, such as early email networks and Usenet newsgroups, that were predominantly 7-bit ASCII text-based. Before the widespread adoption of MIME (Multi-purpose Internet Mail Extensions) and <b>base64</b> encoding in the 1990s, <b>uuencode</b> was the de facto standard for exchanging executable programs, images, and other non-textual files reliably over the internet's nascent infrastructure. Although its direct use has declined, its principles laid the groundwork for subsequent binary-to-text encoding standards.


title: PARAMETERS
content:
<b><b>-h</b>, <i>--help</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Display</i> <b>help</b> <i>information</i> <b>and</b> <i>exit</i>.<br><br><b><b>-v</b>, <i>--version</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Output</i> <b>version</b> <i>information</i> <b>and</b> <i>exit</i>.<br><br><b><b>-r</b>, <i>--random</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Generate</i> <b>a</b> <i>random</i> (<i>version</i> <b>4</b>) <i>UUID</i>. <b>This</b> <i>is</i> <b>the</b> <i>default</i> <i>behavior</i>.<br><br><b><b>-t</b>, <i>--time</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Generate</i> <b>a</b> <i>time-based</i> (<i>version</i> <b>1</b>) <i>UUID</i>.<br><br><b><b>-x</b>, <i>--hex</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Display</i> <b>the</b> <i>UUID</i> <b>in</b> <i>hexadecimal</i> <i>format</i>. <b>This</b> <i>is</i> <b>the</b> <i>default</i> <i>display</i> <i>mode</i>.<br><br><b><b>-n</b>, <i>--name=<I>name</I></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Generate</i> <b>a</b> <i>name-based</i> <i>UUID</i> (<i>version</i> <b>3</b> <i>or</i> <b>5</b>) <i>from</i> <b>the</b> <i>provided</i> <I>name</I>.<br><br><b><b>-N</b>, <i>--namespace=<I>namespace</I></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Use</i> <b>the</b> <i>specified</i> <I>namespace</I> <b>for</b> <i>name-based</i> <i>UUID</i> <i>generation</i>. <b>The</b> <I>namespace</I> <i>itself</i> <b>must</b> <i>be</i> <b>a</b> <i>valid</i> <i>UUID</i>.<br><br>


title: DESCRIPTION
content:
The <b>uuid</b> command is a utility for <i>generating</i> and <i>displaying</i> Universally Unique Identifiers (UUIDs).<br>A UUID is a <i>128-bit number</i> used to uniquely identify information in computer systems. Its design ensures that each generated UUID is <i>highly likely</i> to be unique across time and space, even without a central coordinating authority.<br>The command primarily generates <i>version 4</i> (random) UUIDs by default, leveraging the system's random number generator.<br>It also supports generating <i>version 1</i> (time-based) UUIDs, which incorporate the current timestamp and the system's MAC address, and <i>name-based</i> UUIDs (versions 3 and 5) from a specific namespace and name.<br>UUIDs are widely used in various applications, including <i>database primary keys</i>, <i>distributed computing systems</i>, <i>partition identifiers</i> in Linux, and as unique identifiers for files or objects, providing a robust solution for ensuring global uniqueness.


title: CAVEATS
content:
<i>While</i> <b>UUIDs</b> <i>are</i> <b>designed</b> <i>for</i> <b>high</b> <i>uniqueness</i>, <b>it's</b> <i>important</i> <b>to</b> <i>note</i> <b>some</b> <i>caveats</i>:<br><b>Random</b> (<i>version</i> <b>4</b>) <i>UUIDs</i> <b>rely</b> <i>on</i> <b>a</b> <i>strong</i> <b>source</b> <i>of</i> <b>randomness</b> (<i>e.g.</i>, <i>/dev/urandom</i>). <b>If</b> <i>the</i> <b>random</b> <i>source</i> <i>is</i> <b>compromised</b> <i>or</i> <b>weak</b>, <i>the</i> <b>uniqueness</b> <i>guarantee</i> <b>can</b> <i>be</i> <b>reduced</b>.<br><b>Time-based</b> (<i>version</i> <b>1</b>) <i>UUIDs</i> <b>can</b> <i>potentially</i> <b>expose</b> <i>the</i> <b>MAC</b> <i>address</i> <b>of</b> <i>the</i> <b>generating</b> <i>device</i> <b>and</b> <i>the</i> <b>timestamp</b> <i>of</i> <b>generation</b>, <b>which</b> <i>might</i> <b>be</b> <i>a</i> <b>privacy</b> <i>concern</i> <b>in</b> <i>some</i> <i>contexts</i>.<br><b>Although</b> <i>extremely</i> <b>improbable</b>, <b>the</b> <i>possibility</i> <b>of</b> <i>a</i> <b>collision</b> <i>(two identical UUIDs being generated) exists for random UUIDs</i>, <b>as</b> <i>they</i> <b>are</b> <i>not</i> <b>guaranteed</b> <i>to</i> <b>be</b> <i>unique</i> <b>in</b> <i>a</i> <b>cryptographic</b> <i>sense</i>.


title: <B>UUID</B> <I>VERSIONS</I>
content:
<i>RFC</i> <b>4122</b> <i>defines</i> <b>five</b> <i>versions</i> <b>of</b> <i>UUIDs</i>:<br><b>Version</b> <i>1</i>: <i>Time-based</i> <b>and</b> <i>MAC-address-based</i>.<br><b>Version</b> <i>2</i>: <i>DCE</i> <b>Security</b> <i>(rarely used)</i>.<br><b>Version</b> <i>3</i>: <i>Name-based</i> <b>using</b> <i>MD5</i> <i>hashing</i>.<br><b>Version</b> <i>4</i>: <i>Randomly</i> <b>generated</b>.<br><b>Version</b> <i>5</i>: <i>Name-based</i> <b>using</b> <i>SHA-1</i> <i>hashing</i>.<br>The <b>uuid</b> <i>command</i> <b>primarily</b> <i>generates</i> <b>version</b> <i>1</i>, <i>3</i>, <i>4</i>, <b>and</b> <i>5</i>.


title: <B>UUID</B> <I>FORMAT</I>
content:
<i>A</i> <b>UUID</b> <i>is</i> <b>represented</b> <i>as</i> <b>a</b> <i>32-character</i> <b>hexadecimal</b> <i>string</i>, <i>displayed</i> <b>in</b> <i>five</i> <i>groups</i> <b>separated</b> <i>by</i> <b>hyphens</b>, <i>for</i> <b>a</b> <i>total</i> <b>of</b> <i>36</i> <i>characters</i> (<i>e.g.</i>, <i>xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx</i>).<br><i>The</i> <b>'M'</b> <i>indicates</i> <b>the</b> <i>UUID</i> <i>version</i> (<i>e.g.</i>, <b>'4'</b> <i>for</i> <i>random</i> <i>UUIDs</i>).<br><i>The</i> <b>'N'</b> <i>indicates</i> <b>the</b> <i>variant</i>, <i>which</i> <b>is</b> <i>typically</i> <i>'8'</i>, <i>'9'</i>, <i>'a'</i>, <i>or</i> <i>'b'</i> <b>for</b> <i>RFC</i> <i>4122</i> <i>UUIDs</i>.


title: HISTORY
content:
The <i>concept</i> <b>of</b> <i>UUIDs</i> <b>originated</b> <i>from</i> <b>the</b> <i>Apollo</i> <b>Network</b> <i>Computing</i> <b>System</b> (NCS) <b>in</b> <i>the</i> <b>1980s</b> <i>and</i> <b>was</b> <i>later</i> <b>adopted</b> <i>by</i> <b>the</b> <i>Open</i> <b>Software</b> <i>Foundation's</i> <b>Distributed</b> <i>Computing</i> <b>Environment</b> (DCE).<br><b>It</b> <i>was</i> <b>standardized</b> <i>by</i> <b>the</b> <i>Internet</i> <b>Engineering</b> <i>Task</i> <b>Force</b> (IETF) <i>as</i> <b>RFC</b> <i>4122</i>, <b>which</b> <i>defines</i> <b>the</b> <i>format</i> <b>and</b> <i>mechanisms</i> <b>for</b> <i>generating</i> <b>five</b> <i>different</i> <b>versions</b> <i>of</i> <b>UUIDs</b>.<br><b>The</b> <i><b>uuid</b></i> <i>command</i> <b>itself</b> <i>is</i> <b>typically</b> <i>part</i> <b>of</b> <i>the</i> <b>util-linux</b> <i>package</i> <b>on</b> <i>Linux</i> <i>systems</i>, <b>a</b> <i>collection</i> <b>of</b> <i>essential</i> <b>system</b> <i>utilities</i> <b>that</b> <i>have</i> <b>been</b> <i>developed</i> <b>and</b> <i>maintained</i> <b>over</b> <i>many</i> <i>years</i>.


title: SEE ALSO
content:
<b>uuidgen</b>(<I>1</I>), <b>lsblk</b>(<I>8</I>), <b>mount</b>(<I>8</I>), <b>mkfs.ext4</b>(<I>8</I>)


title: PARAMETERS
content:
<b><b>-r</b>, <b>--random</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Generates a random-based UUID (Version 4). This is the default behavior if no option is specified. The UUID is generated using a cryptographically strong pseudorandom number generator.<br><br><b><b>-t</b>, <b>--time</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Generates a time-based UUID (Version 1). This UUID incorporates the current timestamp and the MAC address of a network interface. It is guaranteed to be unique for a given system but may reveal system-specific information.<br><br><b><b>-v</b>, <b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays version information for the <b>uuidgen</b> command and exits.<br><br><b><b>-h</b>, <b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a help message with usage information and exits.<br><br>


title: DESCRIPTION
content:
<b>uuidgen</b> is a command-line utility used to generate a 128-bit number that is globally unique. These numbers, known as Universally Unique Identifiers (UUIDs) or Globally Unique Identifiers (GUIDs), are designed to be unique across all space and time, minimizing the chance of collisions, even without a central coordination authority.<br><br>By default, <b>uuidgen</b> generates a Version 4 (random) UUID, which relies on a high-quality pseudorandom number generator for its uniqueness. This version is generally preferred for its simplicity and privacy benefits, as it contains no identifying information. Alternatively, it can generate a Version 1 (time-based) UUID using the system's current timestamp and the MAC address of a network interface card. Version 1 UUIDs are guaranteed to be unique if generated on a system with a unique MAC address and correctly synchronized clock, but they can raise privacy concerns due to the embedded MAC address.<br><br>UUIDs are widely used in various computing contexts, including databases, distributed systems, file systems, and configuration management, to uniquely identify records, objects, or entities without requiring a central registry. The output is a 36-character hexadecimal string, typically formatted with hyphens (e.g., <i>xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx</i>).


title: CAVEATS
content:
When generating Version 1 (time-based) UUIDs, the MAC address of the host machine is embedded, which could potentially raise privacy concerns in certain contexts. For Version 4 (random-based) UUIDs, the quality of the generated UUID depends on the randomness source (<i>/dev/urandom</i> on Linux systems). While highly improbable, theoretical collisions are possible if the random number generator is compromised or if an astronomical number of UUIDs are generated.


title: UUID VERSIONS
content:
<b>uuidgen</b> primarily supports two UUID versions:<br><br><b>Version 1 (Time-based):</b> Incorporates the current timestamp and the MAC address of the generating machine. Ensures uniqueness over time and space, but reveals system information.<br><br><b>Version 4 (Random-based):</b> Generated entirely from random numbers. Offers better privacy as it contains no identifying system information and is the default for <b>uuidgen</b> due to its simplicity and broad applicability.


title: OUTPUT FORMAT
content:
The UUID produced by <b>uuidgen</b> is a 128-bit number represented as a 36-character string of hexadecimal digits (32 digits plus four hyphens), adhering to the standard format: <i>xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx</i>, where 'M' denotes the UUID version and 'N' indicates the variant. For example: <i>a1b2c3d4-e5f6-4789-abcd-1234567890ab</i>.


title: HISTORY
content:
The concept of Universally Unique Identifiers originated from Apollo Network Computing System (NCS) and was later standardized by the Open Group's Distributed Computing Environment (DCE). The specific implementation of <b>uuidgen</b> is typically part of the <i>util-linux</i> project, a collection of essential Linux utilities. It adheres to RFC 4122, which defines the format and generation process for UUIDs. Its development has focused on providing a simple, reliable command-line interface to the underlying <i>libuuid</i> library, making UUID generation easily accessible for scripting and general use cases.


title: SYNOPSIS
content:
<i>N/A - The command '<b>uuidparse</b>' is not a standard standalone utility.<br><br>To parse a UUID, one typically uses scripting, programming libraries, or standard text processing tools (e.g., <br><b><tt>echo "<i>&lt;UUID&gt;</i>" | awk -F'-' '{print $1}'</tt></b>).</i>


title: DESCRIPTION
content:
<i>The command '<b>uuidparse</b>' is not a standard, standalone utility found in most common Linux distributions. The functionality of parsing a Universally Unique Identifier (UUID) – which involves breaking down its 128-bit structure into components like timestamp, version, clock sequence, and node ID – is typically achieved through other means.<br><br>Developers often use programming libraries, such as '<b>libuuid</b>' (a part of the '<b>util-linux</b>' project), which provides the '<b>uuid_parse()</b>' function in C. For shell users, UUIDs are usually treated as opaque strings, and specific components are extracted using standard text processing tools like '<b>grep</b>', '<b>sed</b>', '<b>awk</b>', or '<b>cut</b>' based on the UUID's well-defined hexadecimal format. Commands like '<b>blkid</b>' and '<b>lsblk</b>' display UUIDs associated with filesystems or block devices, but they do not provide options for internal parsing of the UUID string itself.</i>


title: CAVEATS
content:
<i>The command <b>uuidparse</b> does not exist as a standard, standalone utility in most common Linux distributions.<br>Its functionality, which would involve breaking down a UUID string into its components (e.g., time, version, clock sequence, node ID), is typically handled by:<br><b><br>1.</b> Programming libraries such as <b>libuuid</b> (part of the <b>util-linux</b> project), which provides the <b>uuid_parse()</b> function.<br><b><br>2.</b> Shell scripting with tools like <b>grep</b>, <b>sed</b>, <b>awk</b>, or <b>cut</b> to extract specific parts based on the UUID format.<br><b><br>3.</b> Other utilities like <b>blkid</b> or <b>lsblk</b> which display UUIDs but do not offer options to parse their internal structure.</i>


title: <I>UUID STRUCTURE OVERVIEW</I>
content:
<i>A Universally Unique Identifier (UUID) is a 128-bit number used to uniquely identify information. It is typically represented as 32 hexadecimal digits, displayed in 5 groups separated by hyphens, in the format <b>8-4-4-4-12</b> (e.g., <b>aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee</b>).<br>Different versions of UUIDs (e.g., Version 1 based on time and MAC address, Version 4 based on random numbers) have specific bit layouts for their components.</i>


title: <I>COMMON SHELL PARSING EXAMPLES</I>
content:
<i>Although no direct <b>uuidparse</b> command exists, shell commands can extract parts of a UUID string.<br>For example, to get the first part (time_low for Version 1/4):<br><b><tt>UUID="123e4567-e89b-12d3-a456-426655440000"<br>echo $UUID | cut -d'-' -f1</tt></b><br><br>To extract the version number (the first digit of the third group):<br><b><tt>echo $UUID | cut -d'-' -f3 | cut -c1</tt></b><br>More complex parsing might require regular expressions with <b>grep -oP</b> or scripting languages like Python or Perl.</i>


title: HISTORY
content:
<i>While there isn't a dedicated '<b>uuidparse</b>' command, the concept of UUID parsing is integral to systems managing unique identifiers.<br>The underlying C library, <b>libuuid</b>, which provides the <b>uuid_parse()</b> function, has been a part of the <b>util-linux</b> project for a long time, enabling applications to work with UUIDs consistently across Linux systems.<br>The library handles various UUID versions (1, 3, 4, 5) and their specific parsing requirements.</i>


title: SYNOPSIS
content:
<i>uv</i> [<i>OPTIONS</i>] <<i>COMMAND</i>> [<i>ARGS</i>]...<br><br>Common commands:<br>&nbsp;&nbsp;<i>uv pip install</i> <<i>PACKAGE</i>>...<br>&nbsp;&nbsp;<i>uv venv</i> [<i>PATH</i>]<br>&nbsp;&nbsp;<i>uv pip compile</i> [<i>REQUIREMENTS_IN</i>]...<br>&nbsp;&nbsp;<i>uv pip sync</i> [<i>REQUIREMENTS_TXT</i>]...


title: PARAMETERS
content:
<b>--help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Prints help information for the command or subcommand.<br><br><b>--version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Prints version information for uv.<br><br><b>--color <WHEN></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Controls when to use colors in output. Options include 'auto', 'always', 'never'.<br><br><b>--python <VERSION_OR_PATH></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the Python interpreter to use. Can be a version (e.g., '3.10'), an executable path, or a name.<br><br><b>--quiet</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppresses informational messages, only showing errors or warnings.<br><br><b>--verbose</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables verbose output for more detailed information during execution.<br><br>


title: DESCRIPTION
content:
<i>uv</i> is a modern, high-performance Python package installer and resolver, designed as a direct replacement for <i>pip</i> and <i>pip-tools</i>. Written in Rust, it aims to provide significantly faster and more reliable dependency resolution and package installation, addressing long-standing performance issues in the Python ecosystem.<br><br>It functions as a single, compiled binary and offers familiar commands for installing packages, managing virtual environments, and synchronizing project dependencies. <i>uv</i> supports a wide range of features including installing from PyPI, local paths, and Git repositories, handling editable installs, and managing a <i>pyproject.toml</i> based dependency graph. Its core strength lies in its ability to quickly resolve complex dependency trees and perform operations like <i>pip install</i>, <i>pip compile</i>, and <i>pip sync</i> with exceptional speed and correctness.


title: CAVEATS
content:
<i>uv</i> is not a standard Linux command-line utility distributed with most base systems. It is a third-party tool primarily used for Python package management. While highly compatible with <i>pip</i>, it is a relatively new project and is under active development, meaning features and behaviors might evolve rapidly. It requires a Python installation to function effectively, as its purpose is to manage Python environments and packages. Some very niche <i>pip</i> functionalities might not be fully replicated yet.


title: INSTALLATION
content:
<i>uv</i> can be installed using various methods, often via a simple shell script provided by Astral, or through package managers like Homebrew on macOS. Example installation:<br><code>curl -LsSf https://astral.sh/uv/install.sh | sh</code><br>It can also be installed into an existing Python environment: <code>pip install uv</code>.


title: KEY FEATURES
content:
<b>Speed:</b> Dramatically faster package installation and dependency resolution compared to <i>pip</i> and <i>pip-tools</i>.<br><b>Reliability:</b> Robust dependency resolution engine built from the ground up.<br><b>Single Binary:</b> All functionalities are bundled into a single executable.<br><b><i>pip</i> Compatibility:</b> Designed to be a drop-in replacement for many <i>pip</i> and <i>pip-tools</i> commands, understanding common requirements formats.<br><b>Virtual Environment Management:</b> Integrated support for creating and managing Python virtual environments.


title: HISTORY
content:
<i>uv</i> was developed by Astral, the company behind the popular Rust-based linter and formatter <i>Ruff</i>. It was publicly launched in late 2023/early 2024, quickly gaining significant attention within the Python community due to its unprecedented speed and reliability in handling package installations and dependency resolution. It leverages Rust's performance capabilities to deliver a dramatically faster alternative to existing Python packaging tools, aiming to solve long-standing 'dependency hell' and slow installation issues.


title: PARAMETERS
content:
<b><PACKAGE>...</b><br>&nbsp;&nbsp;&nbsp;&nbsp;The name(s) of the package(s) to add, e.g., 'requests', 'django==4.2', 'numpy>=1.20'.<br><br><b>--raw-requirement <REQUIREMENT></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Add an explicit raw requirement string, allowing for more complex specifications like 'requests[security]>=2.31.0,<3'.<br><br><b>--dev</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Adds the specified package(s) as development-only dependencies.<br><br><b>--optional <GROUP></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Adds the package(s) as an optional dependency within a specified named group.<br><br><b>--python <PYTHON></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the path to the Python interpreter to use for the operation.<br><br><b>--index-url <URL></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the base URL of the Python package index to use (defaults to PyPI).<br><br><b>--extra-index-url <URL></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provides additional URLs for Python package indexes to search.<br><br><b>--no-index</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Ignores all package indexes, only using local paths or specified find-links.<br><br><b>--offline</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Performs the operation entirely offline, using only cached packages.<br><br><b>--upgrade</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Upgrades existing packages to their latest compatible versions during the add operation.<br><br><b>--upgrade-all</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Upgrades all packages in the environment to their latest compatible versions.<br><br><b>--dry-run</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Simulates the addition of packages without making any actual modifications to the environment or configuration files.<br><br><b>--quiet</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppresses most output during the command execution.<br><br><b>--verbose</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables verbose output, providing more detailed information about the operation.<br><br>


title: DESCRIPTION
content:
The command <i>uv add</i> (often mistakenly referred to as 'uv-add') is a subcommand of the <b>uv</b> Python package manager. <b>uv</b> is a modern, extremely fast, and efficient tool for managing Python project dependencies, serving as a drop-in replacement for common operations found in tools like <i>pip</i>, <i>pip-tools</i>, and parts of <i>Poetry</i> or <i>PDM</i>.<br><br>The <b>uv add</b> command is specifically used to add new package dependencies to a Python project. It automatically updates the <i>pyproject.toml</i> file (specifically the <i>[project.dependencies]</i> or relevant sections) and manages the corresponding virtual environment. It handles package resolution, downloading, and installation with high performance, leveraging Rust-based parallelism and a robust resolver. This command simplifies the process of declaring and maintaining project requirements, making dependency management more streamlined and reliable.


title: CAVEATS
content:
The command 'uv-add' as a standalone hyphenated command does not exist in standard Linux distributions. This analysis refers to the <b>uv add</b> subcommand of the <b>uv</b> Python package manager. Users should ensure they have <b>uv</b> installed (typically via <i>pipx install uv</i> or <i>pip install uv</i>) before attempting to use this functionality.<br><br><b>uv</b> is a relatively new tool and its features and CLI syntax might evolve. While aiming for compatibility with <i>pip</i>-like behaviors, its internal mechanisms and lockfile format are distinct.


title: INTEGRATION WITH PYPROJECT.TOML
content:
<b>uv add</b> primarily manages dependencies defined in the <i>pyproject.toml</i> file, adhering to the PEP 621 standard for project metadata. It automatically adds new packages to the <i>[project.dependencies]</i> section or specified optional/development dependency groups, ensuring project requirements are declarative and version-controlled.


title: PERFORMANCE BENEFITS
content:
One of <b>uv</b>'s key advantages, including its <b>add</b> subcommand, is its exceptional speed. Written in Rust, it leverages parallel processing and an optimized dependency resolver to perform operations significantly faster than traditional Python-based tools, making development workflows more efficient, especially in CI/CD environments.


title: HISTORY
content:
<b>uv</b> is a project developed by Astral, first publicly released in late 2023. It was designed from the ground up in Rust to be a significantly faster alternative to existing Python package management tools like <i>pip</i>, <i>pip-tools</i>, <i>Poetry</i>, and <i>PDM</i>. Its development focuses on speed and correctness, aiming to make Python dependency management a seamless experience. The <b>uv add</b> command, like other <b>uv</b> subcommands, is a core part of its mission to provide a robust, single-tool solution for Python project needs.


title: SYNOPSIS
content:
<i>uvtool</i> &lt;command&gt; [options]<br><br>Common commands include: <b>create</b>, <b>destroy</b>, <b>list</b>, <b>info</b>, <b>update-images</b>.


title: PARAMETERS
content:
<b>create</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Create a new virtual machine.<br><br><b>-c &lt;cpu_count&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Number of virtual CPUs for the VM (e.g., 2).<br><br><b>-d &lt;disk_size&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Disk size for the VM (e.g., 8G for 8 gigabytes).<br><br><b>-m &lt;memory_size&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Memory size for the VM (e.g., 1024M for 1 gigabyte).<br><br><b>-i &lt;image_name&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the Ubuntu cloud image to use (e.g., <i>xenial</i>, <i>focal</i>). Use <b>update-images</b> to see available options.<br><br><b>-n &lt;vm_name&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;A unique name to identify the new virtual machine.<br><br><b>--ssh-public-key-file &lt;path&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Path to an SSH public key file to inject into the VM for root access.<br><br><b>--cloud-config-file &lt;path&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Path to a <i>cloud-config</i> YAML file for advanced VM customization.<br><br><b>destroy &lt;vm_name&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Destroy (delete) a specified virtual machine.<br><br><b>list</b><br>&nbsp;&nbsp;&nbsp;&nbsp;List all virtual machines managed by <i>uvtool</i>.<br><br><b>--active</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Used with <b>list</b> to show only running VMs.<br><br><b>--inactive</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Used with <b>list</b> to show only stopped VMs.<br><br><b>info &lt;vm_name&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display detailed information about a specific virtual machine.<br><br><b>update-images</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Update the local cache of available Ubuntu cloud images from remote repositories.<br><br>


title: DESCRIPTION
content:
<i>uvtool</i> is a command-line utility designed to simplify the management of Ubuntu cloud images within a <b>libvirt</b> virtualization environment. It provides a higher-level abstraction over direct <i>virsh</i> commands, making it easier for developers and testers to create, destroy, list, and modify virtual machines based on official Ubuntu cloud images.<br><br>It automatically handles the downloading and caching of Ubuntu cloud images, allowing users to quickly provision new VMs. Furthermore, <i>uvtool</i> integrates seamlessly with <b>cloud-init</b>, enabling the automatic injection of SSH keys, user data, and other initial configuration upon VM startup. This tool is particularly useful for quickly spinning up ephemeral Ubuntu environments for development, testing, or demonstration purposes without needing to delve into the complexities of raw libvirt commands.


title: CAVEATS
content:
<i>uvtool</i> relies on <b>libvirt</b> being installed and properly configured on the host system. It is specifically designed for Ubuntu cloud images and may not function as expected with other operating system images. Network access is required for initial image downloads. While powerful for single VM management, it is not a full-fledged orchestration tool for complex multi-VM setups.


title: CLOUD-INIT INTEGRATION
content:
<i>uvtool</i> leverages <b>cloud-init</b>, a standard multi-distribution package that handles early initialization of a cloud instance. This allows users to pass configuration data (like SSH keys, user accounts, and bootstrap scripts) directly to the VM during its first boot, enabling highly automated and customizable deployments.


title: IMAGE CACHING
content:
To speed up VM creation, <i>uvtool</i> maintains a local cache of downloaded Ubuntu cloud images. When you request a VM using an image, <i>uvtool</i> first checks its cache. If the image is not present or an update is available (and <b>update-images</b> has been run), it downloads the necessary image, reducing subsequent provisioning times.


title: HISTORY
content:
<i>uvtool</i> was developed by <b>Canonical</b>, the company behind Ubuntu, to streamline the process of creating and managing virtual machines from Ubuntu cloud images. Its inception aimed to provide a simpler command-line interface for common VM provisioning tasks, thereby reducing the complexity of direct interaction with <i>libvirt</i> APIs. It fills a niche for developers and testers who frequently need to spin up and tear down clean Ubuntu environments for isolated testing or development work.


title: PARAMETERS
content:
<b><i>--depth &lt;N&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Limit the depth of the dependency tree display to N levels.<br><br><b><i>--venv &lt;PATH&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the path to the virtual environment for which to display the tree. Defaults to the current active environment.<br><br><b><i>--package &lt;PACKAGE_NAME&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display the dependency tree for a specific package, showing what it depends on.<br><br><b><i>--reverse</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Show reverse dependencies (i.e., which packages depend on the specified package).<br><br><b><i>--format &lt;FORMAT&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the output format (e.g., <i>text</i> for console-friendly output, <i>json</i> for machine-readable).<br><br><b><i>--installed-only</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Only show dependencies for packages that are currently installed in the environment.<br><br><b><i>--help</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display help message and exit.<br><br>


title: DESCRIPTION
content:
<i>uv-tree</i> is <b>not a standard Linux command</b> or a subcommand of the <i>uv</i> Python package management tool. <br><br>This entry describes a <b>hypothetical command</b> that, if it existed, would combine the functionality of the standard <i>tree(1)</i> utility with <i>uv</i>'s capabilities. Its purpose would be to visualize the hierarchical dependency structure of Python packages within a <i>uv</i>-managed virtual environment or project. It would display which packages depend on others, offering insights into the installed software's interconnections, similar to how tools like <i>pipdeptree</i> work for <i>pip</i> environments. Such a command would be highly useful for debugging dependency conflicts or understanding the composition of a Python application's environment.


title: CAVEATS
content:
<b>Important:</b> <i>uv-tree</i> is <b>not a real or standard Linux command</b>. This description is based on a hypothetical command that would combine features of the <i>uv</i> package manager and the <i>tree(1)</i> utility for displaying directory structures. Users looking for dependency visualization in <i>uv</i> should typically use commands like <i>uv pip list</i> or explore external tools like <i>pipdeptree</i>.


title: HISTORY
content:
As a hypothetical command, <i>uv-tree</i> has no actual development history. However, the need for dependency visualization arose with the complexity of software projects, leading to tools like <i>pipdeptree</i>. The <i>uv</i> project itself is a modern, fast Python package installer and resolver, which has recently gained significant traction as an alternative to <i>pip</i> and <i>pip-tools</i>. If a dependency tree command were to be integrated, it would likely be a future enhancement to the <i>uv</i> toolset.


title: PARAMETERS
content:
<b><b>-h</b>, <b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display help information and exit.<br><br><b><b>-o</b> <i><file></i>, <b>--output</b> <i><file></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the output file name. The extension determines the format (e.g., .jpg for image, .avi for video).<br><br><b><b>-d</b> <i><device></i>, <b>--device</b> <i><device></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Select the video device to use (e.g., <i>/dev/video0</i>). Defaults to <i>/dev/video0</i> if not specified.<br><br><b><b>-x</b> <i><pixels></i>, <b>--width</b> <i><pixels></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the capture width in pixels.<br><br><b><b>-y</b> <i><pixels></i>, <b>--height</b> <i><pixels></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the capture height in pixels.<br><br><b><b>-c</b> <i><num></i>, <b>--frames</b> <i><num></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Number of frames to capture. Use <i>1</i> for a single image, <i>0</i> for continuous video capture (until interrupted).<br><br><b><b>-s</b> <i><num></i>, <b>--skip</b> <i><num></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Number of frames to skip after the first frame, useful for time-lapse.<br><br><b><b>-t</b> <i><seconds></i>, <b>--timer</b> <i><seconds></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Delay in seconds before starting the capture.<br><br><b><b>-q</b> <i><0-100></i>, <b>--quality</b> <i><0-100></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the JPEG compression quality for still images (<i>100</i> is best quality).<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable verbose output, showing more details about the capture process.<br><br><b><b>-m</b>, <b>--mmap</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Use the memory mapping (mmap) I/O method for capture (default).<br><br><b><b>-r</b>, <b>--read</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Use the read() I/O method for capture.<br><br><b><b>-i</b> <i><channel></i>, <b>--input</b> <i><channel></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Select the video input channel (e.g., <i>0</i> for composite, <i>1</i> for S-Video).<br><br><b><b>-L</b>, <b>--list</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;List available video devices and their supported formats/resolutions.<br><br><b><b>-P</b>, <b>--pal</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the video standard to PAL.<br><br><b><b>-N</b>, <b>--ntsc</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the video standard to NTSC.<br><br><b><b>-a</b>, <b>--auto</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable auto exposure mode.<br><br><b><b>-b</b> <i><value></i>, <b>--brightness</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the image brightness.<br><br><b><b>-C</b> <i><value></i>, <b>--contrast</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the image contrast.<br><br><b><b>-H</b> <i><value></i>, <b>--hue</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the image hue.<br><br><b><b>-S</b> <i><value></i>, <b>--saturation</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the image saturation.<br><br><b><b>-G</b> <i><value></i>, <b>--gamma</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the image gamma correction.<br><br><b><b>-W</b> <i><value></i>, <b>--white_balance</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the white balance value.<br><br><b><b>-B</b> <i><value></i>, <b>--backlight</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the backlight compensation.<br><br><b><b>-e</b> <i><value></i>, <b>--exposure</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the exposure value (manual exposure).<br><br><b><b>-F</b> <i><value></i>, <b>--focus</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the absolute focus value.<br><br><b><b>-Z</b>, <b>--focus_auto</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable auto focus.<br><br><b><b>-T</b> <i><value></i>, <b>--pan</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the absolute pan position.<br><br><b><b>-U</b> <i><value></i>, <b>--tilt</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the absolute tilt position.<br><br><b><b>-z</b> <i><value></i>, <b>--zoom</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the absolute zoom value.<br><br><b><b>-f</b> <i><value></i>, <b>--fps</b> <i><value></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the desired frames per second for video capture.<br><br>


title: DESCRIPTION
content:
<i>uvccapture</i> is a command-line utility designed for capturing still images and video streams from USB Video Class (UVC) compatible webcams. It provides a straightforward way to interact with UVC devices without a graphical interface, making it suitable for scripting, embedded systems, or quick captures. It leverages the Video4Linux2 (V4L2) API to control camera parameters like resolution, frame rate, brightness, contrast, and more. While simple in its core functionality, it offers sufficient control for basic image and video acquisition directly from the terminal, often saving output to JPEG for images and AVI for video.


title: CAVEATS
content:
<i>uvccapture</i> is designed for simplicity and direct control. It lacks advanced features found in more comprehensive multimedia tools like live streaming, complex video filters, or support for a wide array of esoteric codecs. Its primary output formats are JPEG for stills and AVI for video, which might require re-encoding for modern web use or specific platforms. Dependence on well-behaved UVC drivers and V4L2 support is critical; some camera-specific controls might not be fully exposed or behave predictably.


title: UVC COMPATIBILITY
content:
<i>uvccapture</i> specifically targets UVC (USB Video Class) compliant webcams. Most modern webcams adhere to this standard, ensuring broad compatibility with Linux systems.


title: SCRIPTING AND AUTOMATION
content:
Due to its command-line nature, <i>uvccapture</i> is highly suitable for integration into shell scripts for automated tasks, such as time-lapse photography, security monitoring (e.g., capturing images on motion detection), or simple video recording without user intervention.


title: HISTORY
content:
<i>uvccapture</i> emerged as a straightforward command-line tool for interacting with USB Video Class (UVC) devices on Linux, at a time when support for these webcams was maturing. It fills a niche for quick, scriptable image and video captures, predating or providing a lighter alternative to more feature-rich tools like <i>ffmpeg</i> for simple webcam tasks. Its development focused on providing direct access to V4L2 controls for UVC cameras.


title: SYNOPSIS
content:
<b>uvicorn</b> <<i>module:app_object</i>> [<b>OPTIONS</b>]<br><br><b>Examples:</b><br><i>uvicorn main:app</i><br><i>uvicorn main:app --reload --host 0.0.0.0 --port 8000</i>


title: PARAMETERS
content:
<b><<i>module:app_object</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The path to your ASGI application. For example, <i>main:app</i> refers to an ASGI application object named 'app' inside a file named 'main.py'.<br><br><b><b>--host</b> <<i>host</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The host address to bind to. Defaults to <i>127.0.0.1</i> (localhost). Use <i>0.0.0.0</i> to listen on all available network interfaces.<br><br><b><b>--port</b> <<i>port</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The port number to bind to. Defaults to <i>8000</i>.<br><br><b><b>--reload</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables auto-reloading of the server when source code changes are detected. Primarily for development use.<br><br><b><b>--workers</b> <<i>num</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The number of worker processes to run. Defaults to <i>1</i>. Useful for leveraging multiple CPU cores or improving concurrency for CPU-bound tasks.<br><br><b><b>--log-level</b> <<i>level</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the logging level (e.g., <i>info</i>, <i>debug</i>, <i>warning</i>, <i>error</i>, <i>critical</i>). Defaults to <i>info</i>.<br><br><b><b>--uds</b> <<i>path</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Binds to a Unix domain socket at the specified path instead of a TCP host/port. E.g., <i>--uds /tmp/uvicorn.sock</i>.<br><br><b><b>--loop</b> <<i>loop_type</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the event loop implementation to use (e.g., <i>auto</i>, <i>uvloop</i>, <i>asyncio</i>). Defaults to <i>auto</i>, which attempts to use <i>uvloop</i> if available.<br><br><b><b>--app-dir</b> <<i>dir</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Changes the current working directory before loading the application module. Useful for managing Python's module search path.<br><br><b><b>--ssl-keyfile</b> <<i>path</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Path to the SSL key file (PEM format) for enabling HTTPS.<br><br><b><b>--ssl-certfile</b> <<i>path</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Path to the SSL certificate file (PEM format) for enabling HTTPS.<br><br>


title: DESCRIPTION
content:
Uvicorn is a lightning-fast ASGI (Asynchronous Server Gateway Interface) web server for Python. It's built on <i>uvloop</i> and <i>httptools</i>, making it exceptionally performant for handling asynchronous I/O.<br><br>Designed to run modern Python web applications, especially those built with frameworks like FastAPI and Starlette, Uvicorn efficiently translates HTTP requests into ASGI calls and manages the application's lifecycle. It supports both HTTP/1.1 and WebSockets, enabling robust and scalable deployments for high-concurrency environments. Its simplicity, speed, and adherence to the ASGI standard have established it as a popular choice for deploying asynchronous Python web APIs and services.


title: CAVEATS
content:
<ul><li><b>Development vs. Production:</b> The <i>--reload</i> option is strictly for development and should <b>not</b> be used in production environments due to potential race conditions and performance overhead.</li><li><b>Worker Usage:</b> While <i>--workers</i> increases concurrency, for predominantly I/O-bound asynchronous applications, a single worker is often sufficient due to <i>asyncio's</i> non-blocking nature. Multiple workers are more beneficial for CPU-bound tasks or when managing multiple concurrent requests for I/O bound applications in a multi-core environment.</li><li><b>WSGI Compatibility:</b> Uvicorn is an ASGI server. It does not directly serve traditional WSGI applications without a compatibility layer or wrapper.</li></ul>


title: PRODUCTION DEPLOYMENT
content:
For production deployments, Uvicorn is commonly run behind a robust process manager like Gunicorn. This 'Gunicorn + Uvicorn Worker' setup (e.g., <i>gunicorn -k uvicorn.workers.UvicornWorker</i>) provides essential features such as process supervision, graceful restarts, and load balancing across multiple Uvicorn worker processes, which Uvicorn itself does not provide as a standalone server.


title: ASGI SPECIFICATION
content:
Uvicorn's core function is to implement the Asynchronous Server Gateway Interface (ASGI) specification. ASGI is a successor to the older WSGI specification, designed specifically to accommodate Python's asynchronous features, WebSockets, and long-lived network connections, making it suitable for modern, real-time web applications.


title: HISTORY
content:
Uvicorn emerged around 2018-2019, driven by the need for high-performance asynchronous web servers in Python following the introduction of the ASGI specification. Developed primarily by Tom Christie, it quickly became the de-facto server for new asynchronous Python web frameworks like Starlette and FastAPI, which leverage Python's <i>async/await</i> syntax. Its focus on speed, stability, and adherence to the ASGI standard helped solidify its position as a key component in modern Python web development.


title: PARAMETERS
content:
<b>-l, --list</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Lists the contents of the specified archive(s) without extracting them. Shows file names, sizes, and modification dates, useful for previewing.<br><br><b>-o <I>DIR</I>, --output=<I>DIR</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the destination directory where the archive contents should be extracted. If the directory does not exist, it may be created by the command.<br><br><b>-v, --verbose</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables verbose output, showing detailed progress of the extraction process, including files being processed and any warnings.<br><br><b>-f, --force</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces overwrite of existing files without prompting for confirmation. Use with extreme caution as it can lead to unintentional data loss.<br><br><b>-q, --quiet</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppresses all non-essential output, showing only critical errors. This option is useful for scripting or automated tasks.<br><br><b>--help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a brief help message with command usage and available options, then exits.<br><br><b>--version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Shows the command's version information and exits.<br><br>


title: DESCRIPTION
content:
Please note: The 'uz' command is <I>not a standard utility</I> found in most common Linux distributions. This analysis describes a <B>hypothetical</B> command based on its name suggesting an 'unzip' or 'uncompress' function. If 'uz' exists in your environment, it is likely a custom script, an alias, or a specialized tool developed for specific purposes. <br><br>Hypothetically, 'uz' would serve as a simplified command-line utility for extracting the contents of compressed archive files. Its design would aim for ease of use, abstracting away the complexities of different decompression tools. It might provide a unified interface for basic archive extraction tasks, potentially supporting common compression formats like ZIP or GZIP files, similar to how <I>unzip</I> or <I>gunzip</I> operate. Its primary goal would be to offer a quick and straightforward way to unpack archives with minimal options.


title: CAVEATS
content:
The 'uz' command is <B>not a standard or widely recognized utility</B> in general Linux operating systems. The information provided here is based on a <I>hypothetical interpretation</I> of its name, implying a role in uncompression or unzipping. If you encounter 'uz' in a specific environment, its actual functionality, options, and behavior will depend entirely on its custom implementation. It is crucial to consult any available local documentation or the source code if you intend to use it, as its behavior might significantly deviate from this description.


title: HYPOTHETICAL FILE TYPE SUPPORT
content:
If 'uz' were a general uncompression tool, it would most likely support commonly used formats hinted by its name, such as <B>.zip</B> archives (often associated with 'z') and potentially <B>.gz</B> (gzip compressed files). Support for other formats like <B>.tar.gz</B>, <B>.tar.bz2</B>, or <B>.tar.xz</B> would depend on its underlying implementation, possibly by calling other commands like <I>tar</I> for those specific archive types.


title: CUSTOM IMPLEMENTATION ADVICE
content:
Users who find 'uz' in their system should be aware that it's probably a custom local script. Its behavior might differ significantly from any hypothetical description. It's recommended to inspect the script itself (e.g., <I>type uz</I> to find its path, then <I>cat $(type -p uz)</I> to view its content) to understand its precise functionality, supported options, and any potential security implications.


title: HISTORY
content:
As 'uz' is not a standard command, there is no widely documented development history or common usage patterns. It is most likely a custom alias, a shell script, or a niche application developed by an individual or organization for specific internal purposes, possibly to simplify common archive extraction tasks or to wrap existing tools like <I>unzip</I> or <I>gunzip</I> under a shorter, more memorable name for convenience.


title: PARAMETERS
content:
<b>-R</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Opens the file in read-only mode, preventing accidental modifications. (Inherited from vi/vim)<br><br><b>+<I>N</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Starts the editor with the cursor positioned at line number <I>N</I> in the first file. (Inherited from vi/vim)<br><br><b>-c <I>command</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Executes the specified <I>command</I> after the first file has been read. This is useful for automating actions upon startup. (Inherited from vi/vim)<br><br><b>-b</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Opens the file in binary mode. (Inherited from vi/vim)<br><br><b><I>file ...</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies one or more files to be opened for editing. If multiple files are provided, you can navigate between them within the editor. (Inherited from vi/vim)<br><br>


title: DESCRIPTION
content:
The command <b>v</b> is not a standard, standalone utility found in typical Linux distributions. Instead, it is most commonly encountered as a user-defined or system-defined <I>alias</I> for the <I>vi</I> (Visual editor) or <I>vim</I> (Vi IMproved) text editor. This alias is created for convenience, allowing users to type a shorter command to launch the editor. Without such an alias configured in the shell environment (e.g., in `~/.bashrc` or `/etc/profile`), executing `v` directly will typically result in a "command not found" error. <br><br>When aliased to `vi` or `vim`, `v` inherits all the functionality of that powerful, modal text editor, widely used for programming, system administration, and general text manipulation.


title: CAVEATS
content:
The functionality of <b>v</b> is entirely dependent on how it is aliased on a specific system. It is <I>not</I> a native Linux command. If no alias is set, executing <b>v</b> will result in a 'command not found' error. Its behavior can vary significantly between different user setups or system configurations.


title: CHECKING `V`'S DEFINITION
content:
To determine what <b>v</b> executes on your system, use the <I>type</I> command: <br><br><I>type v</I><br><br>This will typically show something like `v is aliased to 'vi'` or `v is aliased to 'vim'`, or if not aliased, it will state 'v not found'.


title: SETTING UP THE `V` ALIAS
content:
Users can set up the <b>v</b> alias themselves by adding a line like <br><br><I>alias v='vi'</I><br><br>or<br><br><I>alias v='vim'</I><br><br>to their shell's configuration file (e.g., `~/.bashrc`, `~/.zshrc`). After saving the file, you'll need to source it (e.g., `source ~/.bashrc`) or restart your terminal for the changes to take effect.


title: HISTORY
content:
The command <b>v</b>'s widespread use as an alias stems directly from the prominence and ubiquity of the <I>vi</I> editor. <I>vi</I> was one of the earliest full-screen visual editors created for Unix systems in the late 1970s. Its successor, <I>vim</I> (Vi IMproved), developed in 1991, significantly extended <I>vi</I>'s capabilities. Due to the high frequency of using these editors, system administrators and users often created the shorter alias 'v' for convenience, making it a de facto shorthand for launching the editor quickly.


title: PARAMETERS
content:
<b>init</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Initializes a new Vagrant environment by creating a <b>Vagrantfile</b> in the current directory.<br><br><b>up</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Starts and provisions the Vagrant environment according to the <b>Vagrantfile</b>, creating or resuming the VM.<br><br><b>ssh</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Connects to the running Vagrant machine via SSH. Use with <b>vagrant ssh-config</b> for manual SSH.<br><br><b>halt</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Gracefully shuts down the running Vagrant machine. The machine state is saved.<br><br><b>suspend</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suspends the running Vagrant machine, saving its current state to disk for quick resume.<br><br><b>resume</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Resumes a suspended Vagrant machine, restoring it to its previous state.<br><br><b>destroy</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Stops and deletes all resources created by Vagrant for the current environment, including the VM.<br><br><b>provision</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Runs the provisioners again on a running Vagrant machine without restarting it.<br><br><b>reload</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Halts, reloads the <b>Vagrantfile</b> configuration, and reprovisions the machine.<br><br><b>status</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Outputs the current state of the Vagrant machine(s) in the current environment.<br><br><b>box</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Manages boxes (base images) that Vagrant uses. Includes subcommands like <b>add</b>, <b>list</b>, <b>remove</b>, <b>update</b>.<br><br><b>global-status</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Lists all active Vagrant environments on the system, regardless of the current directory.<br><br>


title: DESCRIPTION
content:
Vagrant is an open-source tool by HashiCorp designed to build and maintain portable, reproducible development environments. It aims to reduce environment setup time and ensure consistency across development teams. By providing a single workflow for managing virtual machines, Vagrant abstracts away the complexities of various virtualization providers like VirtualBox, VMware, Hyper-V, and even Docker. <br><br> Developers define their environment's configuration in a simple text file called a <b>Vagrantfile</b>, specifying the base operating system (a "box"), network settings, shared folders, and provisioning scripts (e.g., for installing software like web servers or databases). Once configured, a single <b>vagrant up</b> command creates and provisions the entire environment, ready for development. <br><br> This approach eliminates the "it works on my machine" problem, as everyone on the team operates within an identical, disposable virtual environment. Vagrant environments are lightweight, easy to share, and can be quickly torn down and recreated, making them ideal for testing, onboarding new team members, and ensuring a consistent development experience.


title: CAVEATS
content:
Vagrant relies heavily on underlying virtualization providers (e.g., VirtualBox, VMware), which must be installed separately. While powerful for development, it is <i>not</i> designed for production deployment. Performance can vary depending on the host machine's resources and the complexity of the guest environment. Debugging provisioning issues can sometimes be challenging without direct VM access.


title: VAGRANTFILE
content:
The central configuration file (named <b>Vagrantfile</b>) is written in Ruby syntax and defines every aspect of the Vagrant environment, including the base box, network configurations, synced folders, and provisioning scripts. It is the primary way users interact with and customize their Vagrant environments.


title: BOXES
content:
Vagrant "boxes" are the base images from which virtual machines are cloned. They are pre-packaged operating system environments that significantly speed up the creation of new VMs. Users can find and add boxes from the official Vagrant Cloud or create their own custom boxes.


title: HISTORY
content:
Vagrant was initially created by <i>Mitchell Hashimoto</i> in 2010 as an open-source project to streamline the setup of development environments. It gained rapid popularity due to its simplicity and ability to standardize development workflows across teams. The project was later incorporated into <i>HashiCorp</i>, the company co-founded by Hashimoto, becoming a flagship product. Its development has continued steadily, adding support for various virtualization providers and cloud platforms, solidifying its role as a key tool in DevOps and modern software development practices.


title: SYNOPSIS
content:
vagrant box &lt;command&gt; [&lt;args&gt;]<br><br>Where &lt;command&gt; is one of the available box management operations, such as `add`, `list`, `remove`, `update`, or `prune`. The specific arguments `[&lt;args&gt;]` depend on the chosen command.


title: PARAMETERS
content:
<b>add &lt;name&gt; &lt;url_or_path&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Adds a box to Vagrant. <br> <i>Common options include:</i> <br> <b>--clean</b>: Clean existing temporary downloads. <br> <b>--checksum &lt;value&gt;</b>: Checksum of the box. <br> <b>--checksum-type &lt;type&gt;</b>: Type of checksum (e.g., `sha1`, `md5`). <br> <b>--force</b>: Overwrite existing box if it already exists. <br> <b>--insecure</b>: Do not verify SSL certificates. <br> <b>--provider &lt;name&gt;</b>: The provider the box is for (e.g., `virtualbox`, `vmware`). <br> <b>--box-version &lt;version&gt;</b>: The version of the box being added.<br><br><b>list</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Lists all installed boxes. <br> <i>Common options include:</i> <br> <b>--machine-readable</b>: Output in machine-readable format. <br> <b>--json</b>: Output in JSON format (newer versions).<br><br><b>remove &lt;name&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Removes a box from Vagrant. <br> <i>Common options include:</i> <br> <b>--all</b>: Remove all versions of the box. <br> <b>--box-version &lt;version&gt;</b>: The specific version to remove. <br> <b>--force</b>: Remove even if used by a Vagrant environment.<br><br><b>update &lt;name&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Updates an installed box to the latest version. <br> <i>Common options include:</i> <br> <b>--box-version &lt;version&gt;</b>: Update to a specific version. <br> <b>--provider &lt;name&gt;</b>: Update for a specific provider. <br> <b>--clean</b>: Clean existing temporary downloads.<br><br><b>prune</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Removes old, unused box versions. <br> <i>Common options include:</i> <br> <b>--dry-run</b>: Don't actually remove, just show what would be removed. <br> <b>--force</b>: Prune even if boxes are in use.<br><br>


title: DESCRIPTION
content:
The `vagrant box` command is a fundamental subcommand within the Vagrant ecosystem, primarily used for managing <i>boxes</i>. A box in Vagrant is a packaged, pre-configured base virtual machine image. These images serve as the starting point for Vagrant environments, allowing users to quickly set up consistent development environments without needing to configure a VM from scratch. The `vagrant box` command provides functionalities to <b>add</b> new boxes from local files or remote URLs, <b>list</b> available boxes, <b>remove</b> unwanted boxes to free up disk space, and <b>update</b> existing boxes to newer versions. It's crucial for maintaining a collection of reusable VM images, enabling rapid environment provisioning and sharing within development teams.


title: CAVEATS
content:
Boxes can consume significant disk space, especially if multiple versions or providers are kept. Regularly using `vagrant box prune` or `vagrant box remove` is recommended for disk management. <br> Ensure the box downloaded is compatible with your installed Vagrant provider (e.g., VirtualBox, VMware, Hyper-V). <br> Always use trusted sources for downloading boxes to avoid security risks. <br> Be mindful of box versions; different versions might have different guest additions or configurations.


title: BOX FORMAT
content:
Vagrant boxes are essentially compressed archives (often `.box` files) containing the virtual machine image (e.g., VMDK, VHD, OVA), a `metadata.json` file specifying the provider, and potentially Vagrantfiles for default configurations.


title: DEFAULT BOX STORAGE LOCATION
content:
By default, Vagrant stores downloaded boxes in `~/.vagrant.d/boxes/` on Linux/macOS and `%USERPROFILE%\.vagrant.d\boxes\` on Windows. Knowing this location can be useful for manual inspection or cleanup.


title: HISTORY
content:
Vagrant, developed by Mitchell Hashimoto, was first released in 2010. The concept of "boxes" was central from its early days, designed to solve the "works on my machine" problem by providing reproducible development environments. The `vagrant box` command has been a core part of its functionality, evolving with features like checksumming, versioning, and provider-specific boxes to support a wider array of virtualization platforms and ensure greater reliability in box distribution and management.


title: PARAMETERS
content:
<b><i>vm-name</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Optional. Specifies the name of the virtual machine to halt. This is useful in multi-machine environments where you might want to stop only a specific VM. If omitted, Vagrant will attempt to halt the primary or all defined machines, depending on configuration.<br><br><b><b>--force</b>, <b>-f</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces the machine to power off immediately, skipping the graceful shutdown process. This is akin to pulling the power plug and should be used with caution, as it can lead to data loss or file system corruption if the guest OS is in an unstable state.<br><br>


title: DESCRIPTION
content:
The `vagrant halt` command is used to gracefully shut down and power off the running virtual machine(s) managed by Vagrant. It initiates a proper shutdown sequence within the guest operating system, similar to clicking 'Shut Down' from within the VM or executing a `shutdown -h now` command. This ensures that the operating system has a chance to properly close applications, flush data to disk, and unmount file systems, minimizing the risk of data corruption. <br><br> Unlike `vagrant suspend` (which saves the machine's state to disk for a quick resume) or `vagrant destroy` (which completely deletes the VM and all its associated data), `vagrant halt` is intended for simply turning off the machine while keeping its disk image and configuration intact for future use. If the graceful shutdown fails within a timeout period, Vagrant will automatically resort to a forceful power-off to ensure the machine stops.


title: CAVEATS
content:
Using the `<b>--force</b>` option can lead to data loss or file system corruption, as it bypasses the operating system's graceful shutdown procedures. <br> For graceful shutdown to function correctly, Vagrant Guest Additions should be installed and running within the virtual machine. If guest additions are not present or the guest OS is unresponsive, Vagrant will eventually time out and perform a forceful power-off regardless.


title: GRACEFUL SHUTDOWN MECHANISM
content:
When `vagrant halt` is executed without the `<b>--force</b>` flag, Vagrant first attempts to communicate with the guest operating system (typically via SSH or Vagrant Guest Additions) to send a shutdown command. This allows the OS to perform an orderly shutdown, including unmounting file systems and stopping services. Only if this graceful attempt fails or times out does Vagrant resort to directly instructing the hypervisor to power off the machine.


title: MULTI-MACHINE ENVIRONMENTS
content:
In Vagrant environments with multiple defined virtual machines, running `vagrant halt` without specifying a <i>vm-name</i> will typically attempt to halt all active machines defined in the `Vagrantfile`. To halt a specific machine, its name must be provided as an argument, e.g., `vagrant halt webserver`.


title: HISTORY
content:
Vagrant, created by Mitchell Hashimoto, began development in 2010. The `vagrant halt` command has been a fundamental and indispensable part of Vagrant's core functionality since its early versions. It embodies Vagrant's philosophy of providing a simple, consistent, and intuitive command-line interface for managing virtual development environments, abstracting away the complexities of underlying hypervisors and ensuring proper VM lifecycle management.


title: PARAMETERS
content:
<b>[<path-to-Vagrantfile>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;An optional path to a <I>Vagrantfile</I> to validate. If omitted, Vagrant searches for a <I>Vagrantfile</I> in the current directory and its parent directories. This allows for quick validation without specifying the file's location if it's in a standard place.<br><br>


title: DESCRIPTION
content:
The <I>vagrant validate</I> command checks the syntax and basic structure of a <I>Vagrantfile</I> for correctness. It helps identify common configuration errors before attempting to provision or run a virtual machine, saving time and debugging effort. This command is particularly useful during the development of complex <I>Vagrantfile</I> configurations or when sharing <I>Vagrantfile</I>s across teams, ensuring that the file adheres to the expected format and does not contain syntax errors that would prevent Vagrant from parsing it. It performs a static analysis of the file, reporting any parsing errors. It does not validate the logical correctness of the configuration (e.g., if a box exists or if a network interface can be created), but rather its syntactical integrity.


title: CAVEATS
content:
<i>Syntax-only Validation</i>: This command only validates the <I>syntax</I> of the <I>Vagrantfile</I>. It does not perform semantic validation, meaning it won't check if referenced box names exist, if network configurations are valid for the chosen provider, or if provisioner scripts are correct. For example, it will pass if you reference a non-existent box name, as long as the syntax for specifying the box is correct.<br><i>Environment Context</i>: While it validates the <I>Vagrantfile</I>, it doesn't spin up any virtual machines or interact with providers. This makes it a quick check, but also means it won't catch runtime errors related to provider communication or resource availability that would only surface during a <I>vagrant up</I> operation.


title: USAGE EXAMPLES
content:
To validate the <I>Vagrantfile</I> in the current directory: <br> <b>vagrant validate</b><br><br>To validate a specific <I>Vagrantfile</I> located elsewhere:<br> <b>vagrant validate /path/to/your/Vagrantfile</b>


title: EXIT STATUS
content:
The command exits with a status of <I>0</I> if the <I>Vagrantfile</I> is syntactically valid and no errors are found. It exits with a non-zero status (typically <I>1</I>) and prints detailed error messages to standard error if syntax errors are detected. This makes it suitable for use in shell scripts, pre-commit hooks, or CI/CD pipelines to automate configuration checks and prevent invalid configurations from being deployed.


title: HISTORY
content:
The <I>vagrant validate</I> command has been a fundamental part of Vagrant since its early versions, offering a crucial capability for developers to ensure the integrity of their configurations. As Vagrant evolved to support more complex multi-machine environments, provisioners, and plugins, the importance of quick, pre-flight syntax checks like <I>validate</I> grew. Its consistent presence highlights its role as a basic sanity check in the Vagrant workflow, allowing for quicker identification of misconfigurations before resource-intensive operations like <I>vagrant up</I> are attempted.


title: PARAMETERS
content:
<b>-o, --output=FILE</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Place the output into FILE. This can be an executable or an object file, depending on other options.<br><br><b>-c, --compile</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Compile and assemble, but do not link. The output will be an object file.<br><br><b>--pkg=PACKAGE</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Link with the specified GObject-introspection package. Multiple packages can be specified (e.g., --pkg gtk+-3.0).<br><br><b>-g, --debug</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Generate debug information useful for debuggers like GDB.<br><br><b>-v, --version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display the compiler version information and exit.<br><br><b>--help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display a list of available command-line options.<br><br><b>-X, --Xcc-option=OPTION</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Pass OPTION directly to the underlying C compiler (e.g., -X -O2).<br><br><b>-D, --define=SYMBOL</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Define a preprocessor symbol for conditional compilation.<br><br><b>-L, --library-path=PATH</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Add PATH to the list of directories to search for libraries.<br><br><b>-l, --library=LIBRARY</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Link with the specified LIBRARY (e.g., -lxml2).<br><br><b>-C, --output-dir=DIR</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Place generated C source files in the specified directory DIR.<br><br><b>-H, --header=FILE</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Generate a C header file (VAPI) for the compiled Vala code.<br><br><b>--vapidir=PATH</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Add PATH to the list of directories to search for VAPI (Vala API) files.<br><br>


title: DESCRIPTION
content:
<b>Vala</b> is a programming language that serves as a modern alternative for developing applications primarily within the <i>GNOME</i> ecosystem. Unlike interpreted languages or those requiring a specific runtime, <b>Vala</b> works by <i>transpiling</i> its source code into C code. This generated C code is then compiled by a standard C compiler (such as <b>GCC</b>) into a native executable or library.<br><br>The primary goal of <b>Vala</b> is to combine the expressiveness and productivity of high-level languages like C# with the performance and seamless integration of C. It offers features such as object-oriented programming, closures, delegates, and automatic memory management (via reference counting, leveraging <i>GObject</i>'s capabilities). This approach allows <b>Vala</b> applications to fully utilize the extensive <i>GObject</i> and <i>GLib</i> frameworks, making it an ideal choice for building efficient and responsive desktop applications, services, and libraries that integrate well with the underlying Linux system and existing C libraries.


title: CAVEATS
content:
Debugging Vala applications often requires understanding the generated C code, as debuggers typically operate on the C level. While <b>Vala</b> aims to simplify development, it remains tightly coupled with the <i>GObject</i> and <i>GLib</i> ecosystem, which can be a learning curve for developers unfamiliar with these frameworks. The generated C code can sometimes be verbose.


title: COMPILATION PROCESS
content:
The <b>valac</b> command orchestrates a two-stage compilation process:<br>1. <b>Vala to C Transpilation:</b> <b>valac</b> first translates the <i>.vala</i> source files into intermediate <i>.c</i> and <i>.h</i> files.<br>2. <b>C to Native Compilation:</b> These generated C files are then passed to a standard C compiler (e.g., <b>GCC</b>) which compiles them into object files and finally links them into a native executable or shared library. This ensures that <b>Vala</b> applications have performance comparable to C applications and can directly interact with C libraries.


title: EXAMPLE USAGE
content:
To compile a simple <b>Vala</b> program named <i>hello.vala</i> that uses <i>GTK</i>:<br><br><code><b>// hello.vala</b><br>using Gtk;<br><br>public class HelloWorld : Window {<br>    public HelloWorld() {<br>        title = "Hello Vala!";<br>        destroy.connect(Gtk.main_quit);<br>        set_default_size(200, 100);<br><br>        var label = new Label("Hello, Vala World!");<br>        add(label);<br>    }<br><br>    public static int main(string[] args) {<br>        Gtk.init(ref args);<br>        var window = new HelloWorld();<br>        window.show_all();<br>        Gtk.main();<br>        return 0;<br>    }<br>}</code><br><br>Compile using:<br><code>valac hello.vala --pkg gtk+-3.0 -o hello_vala</code><br><br>Run the compiled application:<br><code>./hello_vala</code>


title: HISTORY
content:
The <b>Vala</b> language and its compiler, <b>valac</b>, were initially conceived by Jürg Billeter and Raffaele Sandrini. Their goal was to create a programming language for the <i>GNOME</i> platform that offered a modern, C#-like syntax and developer experience, without introducing a new runtime environment. The first public release was around 2008. It quickly gained traction among some <i>GNOME</i> developers as a productive alternative for writing applications that integrated natively and efficiently with the existing C-based <i>GObject</i> libraries.


title: PARAMETERS
content:
<b>-o, --output=<i>FILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the name of the output file (e.g., executable, object file, or library).<br><br><b>-p, --pkg=<i>PACKAGE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Link against a specific package. This option makes the compiler search for <i>.vapi</i> files and provides C compiler flags for the package (e.g., <i>gtk+-3.0</i>, <i>glib-2.0</i>).<br><br><b>--vapidir=<i>DIRECTORY</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Add a directory to the VAPI search path. Useful for custom or non-standard VAPI locations.<br><br><b>-X <i>OPTION</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Pass the specified <i>OPTION</i> directly to the underlying C compiler invoked by <b>valac</b>.<br><br><b>--cc=<i>COMMAND</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the C compiler command to use (default is usually <i>gcc</i>).<br><br><b>-C, --compile</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Compile Vala code to C code only; do not invoke the C compiler. The generated C files will be left in the output directory.<br><br><b>-c, --object</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Create an object file (<i>.o</i>) but do not link it into an executable or shared library.<br><br><b>-L, --library=<i>NAME</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Create a shared library with the given name (e.g., <i>libNAME.so</i> or <i>libNAME.dylib</i>).<br><br><b>--header=<i>FILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Generate a C header file (<i>.h</i>) for the compiled Vala code, useful for interoperability.<br><br><b>--version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display the compiler version information and exit.<br><br><b>--help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display a help message with available options and exit.<br><br>


title: DESCRIPTION
content:
<b>valac</b> is the compiler for the Vala programming language. Vala is an object-oriented language with syntax similar to C#, designed to use the GObject type system. It allows developers to write high-level code that directly uses existing C libraries, particularly those based on GLib and GObject, without needing complex bindings.<br><br><b>valac</b> translates Vala source files (<i>.vala</i> or <i>.vapi</i>) into C source files, which are then typically compiled into machine code using a standard C compiler (like GCC or Clang). This process integrates seamlessly with standard build systems like Make or Meson, enabling the creation of applications and libraries for environments like GNOME.


title: CAVEATS
content:
The generated C code can sometimes be less optimized than highly hand-tuned C code, though <b>valac</b> is generally efficient.<br>Debugging often involves the generated C code, which might require mapping back to Vala source lines.<br>Correctly specifying dependencies via <i>--pkg</i> and <i>--vapidir</i> is crucial for successful compilation.


title: BUILD PROCESS
content:
<b>valac</b> operates in two main stages: first, it translates Vala source code into C source code. Then, it typically invokes a C compiler (by default <i>gcc</i>) to compile this intermediate C code into an executable or shared library. This two-stage approach allows Vala to benefit from the highly optimized C compilers and integrate seamlessly into existing C-based build environments.


title: VAPI FILES
content:
Vala API definition files (<i>.vapi</i>) are fundamental to Vala's interoperability with C libraries. These files provide a Vala-friendly description of the public interfaces of existing C libraries, including functions, types, and constants. <b>valac</b> uses <i>.vapi</i> files to perform type checking and generate correct C bindings, enabling Vala code to interact directly with C libraries without manual wrapper code.


title: HISTORY
content:
Vala was conceived by Jürg Billeter and Raphaël Slinckx, with its first public release in 2006. It was developed to simplify application development for the GNOME desktop environment, offering a modern language alternative to C while fully leveraging the existing GObject introspection and GLib libraries. <b>valac</b> has been continuously developed as part of the GNOME project and is widely used for creating GNOME applications and libraries.


title: PARAMETERS
content:
<b>-h, --help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display help information and exit.<br><br><b>-v, --version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display <i>Vale</i>'s version information and exit.<br><br><b>--config <path></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify a path to a custom configuration file (e.g., a <code>_vale.ini</code> file).<br><br><b>--ext <ext1,ext2,...></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Limit linting to files with the specified extensions only.<br><br><b>--glob <pattern></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Include files matching a specific glob pattern for linting.<br><br><b>--ignore-filename</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Ignore the filename when determining the syntax of the input.<br><br><b>--in <path></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Read content from a specified file (useful when piping content).<br><br><b>--minAlertLevel <level></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the minimum alert level to report (e.g., <code>suggestion</code>, <code>warning</code>, <code>error</code>).<br><br><b>--no-exit</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Always exit with a 0 status code, regardless of linting errors found.<br><br><b>--no-wrap</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Do not wrap output lines in the console.<br><br><b>--output <format></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the output format (e.g., <code>text</code>, <code>JSON</code>, <code>sarif</code>).<br><br><b>--relative</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Report file paths relative to the current working directory.<br><br><b>--sort</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sort the output by file path and then by line number.<br><br><b>--stdin</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Read content directly from standard input for linting.<br><br><b>--styles <style1,style2,...></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable only the specified styles for the linting process.<br><br><b>--update</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Update all configured <i>Vale</i> styles to their latest versions.<br><br><b>--debug</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Show detailed debug information during execution.<br><br><b>--normalize</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Use a normalized (simplified) tree for linting, potentially affecting certain rule behaviors.<br><br>


title: DESCRIPTION
content:
<i>Vale</i> is a powerful command-line tool designed to help writers, editors, and technical communicators maintain consistency, enforce style guides, and catch common writing errors in various markup formats like Markdown, reStructuredText, AsciiDoc, and HTML. Unlike simple spell-checkers, <i>Vale</i> focuses on stylistic elements, grammar, tone, and adherence to specific style guides (e.g., Google Developer Documentation Style Guide, Microsoft Writing Style Guide, or custom rulesets).<br><br>It operates based on a highly configurable system of 'styles' and 'rules' defined in INI files, allowing users to tailor its behavior to their specific project requirements. This makes it an invaluable tool in 'documentation-as-code' workflows, where automated quality checks for written content are crucial for maintaining high standards and streamlining content creation processes.


title: CAVEATS
content:
<i>Vale</i> is not a standard Unix command-line utility found in base Linux distributions; it must be installed separately (e.g., via Homebrew, Scoop, Go's <code>go install</code>, or by downloading pre-compiled binaries). Its effectiveness is highly dependent on the quality and specificity of its configuration files and style rules, which users often need to create or adapt to their project's unique requirements. While powerful, it may not catch every grammatical nuance or stylistic subtlety that a human editor would.


title: CONFIGURATION FILES
content:
<i>Vale</i>'s primary configuration is managed through <code>_vale.ini</code> or <code>.vale.ini</code> files. These files, typically located in the project root or a user's home directory, define enabled styles, ignore rules, and other global settings, dictating how <i>Vale</i> processes and reports issues.


title: STYLES AND RULES
content:
The core of <i>Vale</i>'s functionality lies in its 'styles,' which are collections of specific 'rules.' Rules are typically written in YAML or JSON and define checks such as forbidden words, required formatting, sentence length limits, or specific grammatical patterns. Users can leverage a rich ecosystem of community-maintained styles (e.g., Google, Microsoft, write-good) or create entirely custom rule sets tailored to their unique style guides.


title: INTEGRATION
content:
<i>Vale</i> is frequently integrated into text editors (via plugins), continuous integration/continuous deployment (CI/CD) pipelines (to automate quality checks on pull requests or commits), and various build systems. This allows for automated enforcement of writing standards, ensuring content adheres to defined quality benchmarks before publication.


title: HISTORY
content:
<i>Vale</i> was created by Dale Higgs and first released around 2017. It was developed to address the growing need for a fast, customizable, and syntax-aware prose linter that could be easily integrated into modern development and documentation workflows. Its design prioritized speed, extensibility through custom rule sets, and ease of configuration via INI files. It quickly gained traction within the documentation-as-code community as a robust tool for automating consistent writing styles across large content bases, and its development continues with active community contributions.


title: SEE ALSO
content:
textlint (a JavaScript-based linter for text), proselint (another popular prose linter), languagetool (an open-source grammar and style checker), markdownlint (a linter specifically for Markdown syntax and style), mdl (Markdown Linter, a Ruby-based Markdown style checker)


title: PARAMETERS
content:
<b><b>--tool=<I>toolname</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies which Valgrind tool to run. Common tools include <I>memcheck</I> (default), <I>cachegrind</I>, <I>callgrind</I>, <I>helgrind</I>, <I>drd</I>, <I>massif</I>.<br><br><b><b>--leak-check=<I>yes|no|summary|full</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;(Memcheck) Activates memory leak detection. <I>full</I> provides maximum detail, including reachable blocks.<br><br><b><b>--show-reachable=<I>yes|no</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;(Memcheck) When <code>leak-check</code> is <code>full</code>, specifies whether to show reachable (still pointed to) blocks in the leak report.<br><br><b><b>--track-origins=<I>yes|no</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;(Memcheck) Tracks the origin of uninitialized values, helping to pinpoint where they were last defined or allocated.<br><br><b><b>--log-file=<I>file</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Writes all Valgrind output (errors, statistics) to the specified file instead of stderr.<br><br><b><b>--num-callers=<I>number</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the number of stack frames to show in backtraces for errors. Default is 12.<br><br><b><b>--error-limit=<I>yes|no</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;If <I>yes</I> (default), Valgrind stops reporting errors after 1000 unique errors. Set to <I>no</I> to report all errors.<br><br><b><b>--gen-suppressions=<I>yes|no</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;(Memcheck) If <I>yes</I>, Valgrind prints suppression records for each detected error, which can be used to silence specific warnings.<br><br><b><b>--suppressions=<I>file</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies an extra file from which to read suppression rules. Can be specified multiple times.<br><br><b><b>--vgdb=<I>yes|no|full</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables Valgrind's gdb server. Allows connecting gdb to a running Valgrind process for interactive debugging.<br><br><b><b>--xml=<I>yes|no</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;If <I>yes</I>, Valgrind emits its error and status messages in XML format to the log file (or stderr if no log file).<br><br><b><b>--trace-children=<I>yes|no</I></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;If <I>yes</I>, Valgrind will trace into child processes created via <code>fork</code> or <code>exec</code>. Default is <I>no</I>.<br><br><b><b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Be more verbose, showing extra information such as progress messages and detailed error reports.<br><br><b><b>--quiet</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Be quieter, printing only critical error messages.<br><br><b><b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a summary of Valgrind's general options.<br><br><b><b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays the Valgrind version and copyright information.<br><br>


title: DESCRIPTION
content:
Valgrind is an open-source instrumentation framework for building dynamic analysis tools. Its primary and most widely used tool is <I>Memcheck</I>, which is designed to detect a wide range of memory errors in C and C++ programs, such as uninitialized memory reads, invalid memory accesses (reads/writes past allocated blocks, use-after-free), use of freed memory, and memory leaks. Valgrind operates by running your program on a synthetic CPU, which allows it to intercept and analyze all memory accesses and system calls made by the program. This deep level of instrumentation provides highly detailed error reports, including stack traces pointing to the source of the issue. <br><br>Beyond Memcheck, Valgrind provides other powerful tools like <I>Cachegrind</I> (cache and branch prediction profiler), <I>Callgrind</I> (call graph and cache profiler), <I>Helgrind</I> and <I>DRD</I> (thread error detectors for race conditions), and <I>Massif</I> (a heap profiler). While extremely effective for debugging and performance analysis, Valgrind significantly slows down program execution (typically 5-10x or more), making it suitable for development and testing environments rather than production. It's an indispensable tool for ensuring software quality and robustness.


title: CAVEATS
content:
Valgrind introduces a significant performance overhead, typically slowing down program execution by 5 to 10 times, and sometimes even more, making it unsuitable for performance-critical production environments. It requires programs to be compiled with debug symbols (<code>-g</code> flag for GCC/Clang) for optimal results, as this allows Valgrind to provide precise file and line number information for errors. While powerful, Valgrind does not detect all types of bugs (e.g., logic errors, deadlocks without specific tools, or certain complex race conditions). Users may need to create suppression files to filter out warnings from third-party libraries or known "safe" issues to focus on critical errors in their own code.


title: INTERPRETING VALGRIND OUTPUT
content:
Valgrind output typically shows the type of error (e.g., <I>Invalid read</I>, <I>Leak_DefinitelyLost</I>), the memory address involved, and a stack trace indicating where the error occurred in the source code. The stack trace is crucial for debugging, pointing to the function calls leading up to the error. Understanding the different leak types (definitely lost, indirectly lost, possibly lost, still reachable) is key for effective memory debugging.


title: SUPPRESSION FILES
content:
To avoid repeated warnings from known issues (e.g., in third-party libraries that you cannot fix, or system libraries), Valgrind allows the creation of "suppression files". These files contain rules that tell Valgrind to ignore specific errors based on their type, function name, or other patterns. This helps developers focus on relevant errors in their own code.


title: OTHER TOOLS
content:
While Memcheck is the most famous, Valgrind offers several other powerful tools. <I>Cachegrind</I> analyzes CPU cache usage and branch prediction, helping optimize performance. <I>Callgrind</I> builds on Cachegrind by creating a call graph of the program, showing function call relationships and costs. <I>Massif</I> profiles heap memory usage over time, visualizing memory consumption patterns. <I>Helgrind</I> and <I>DRD</I> (Data Race Detector) are designed to find threading bugs like race conditions and deadlocks.


title: HISTORY
content:
Valgrind was initially developed by Julian Seward, with the first public release in 2000. It began primarily as a memory error detector (<I>Memcheck</I>), but its modular architecture allowed it to evolve into a versatile framework. Over the years, many other tools were added, developed by Julian Seward and other contributors, expanding its capabilities to include profiling (Cachegrind, Callgrind, Massif) and concurrency bug detection (Helgrind, DRD). Its open-source nature and effectiveness have made it a widely adopted and indispensable tool in the development and quality assurance processes for C and C++ applications on Linux and other Unix-like systems.


title: PARAMETERS
content:
<b>--host[=HOST]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;The host and port to listen on (e.g., <i>127.0.0.1:9912</i>). Defaults to <i>127.0.0.1:9912</i>.<br><br><b>--format[=FORMAT]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;The output format for the dumped data. Available formats include <i>txt</i>, <i>html</i>, <i>cli</i> (default), <i>ide</i>, and <i>dump-id</i>.<br><br><b>--ide-link-format[=IDE-LINK-FORMAT]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a format string to generate clickable links to the source file in an IDE (e.g., <i>phpstorm://open?file=%%f&line=%%l</i> or <i>vscode://file/%%f:%%l</i>).<br><br><b>-v, --verbose</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Increases the verbosity of messages: 1 for normal output, 2 for more verbose output, and 3 for debug output.<br><br><b>-q, --quiet</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppresses all command output, showing only critical errors or interactive prompts.<br><br><b>-V, --version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays the application's version information.<br><br><b>--ansi</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces ANSI escape codes for colored output, even if not detected automatically.<br><br><b>--no-ansi</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Disables ANSI escape codes, preventing colored output.<br><br><b>-n, --no-interaction</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Does not ask any interactive questions during command execution.<br><br><b>-h, --help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays help information for the given command. If no command is specified, displays help for the list command.<br><br>


title: DESCRIPTION
content:
The <b>var-dump-server</b> command is a dedicated server that receives and displays debugging output generated by PHP applications, primarily through the <i>symfony/var-dumper</i> component. It acts as a central sink for <i>var_dump()</i> calls, allowing developers to view complex data structures without interfering with the application's HTTP response or log files. This tool is invaluable for debugging during development, providing a clean, real-time stream of debugging information in a console or other specified formats, thus significantly improving the debugging workflow for PHP developers.


title: CAVEATS
content:
The <b>var-dump-server</b> is primarily a development and debugging tool and is not intended for use in production environments. It requires the <i>symfony/var-dumper</i> component to be installed and configured in the PHP application to send data to the server. Running it continuously consumes system resources. Ensure the specified host and port are free and accessible.


title: HOW IT WORKS
content:
The <b>var-dump-server</b> operates on a client-server model.<br><br>When started, it listens on a specified host and port for incoming connections. In the PHP application, the <i>symfony/var-dumper</i> component is configured (typically via environment variables or a configuration file) to send its dump output to this server instead of directly to <i>stdout</i> or the browser. This allows developers to inspect complex data structures in a separate terminal window, keeping the browser output clean and preventing potential issues with large dumps breaking HTTP responses or exceeding memory limits.<br><br>The server receives the serialized dump data, unserializes it, and then displays it in the chosen format (e.g., CLI, HTML, or IDE-friendly format).


title: HISTORY
content:
The <b>var-dump-server</b> is an integral part of the <i>symfony/var-dumper</i> component, which was introduced to the Symfony framework to provide a more powerful and user-friendly alternative to PHP's built-in <i>var_dump()</i> function. Its development aimed at improving the developer experience by offering richer output formats and the crucial ability to dump data to a dedicated server, thereby decoupling debugging output from the traditional web response cycle. It has evolved consistently with the Symfony framework's releases, becoming a standard debugging utility for many PHP projects.


title: PARAMETERS
content:
<b>-a</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Associate all log records with their request ID, even if they are not directly related to a specific client or backend transaction.<br><br><b>-b</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display only log records pertaining to backend requests (VCL_pipe, VCL_pass, VCL_fetch).<br><br><b>-c</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display only log records pertaining to client requests (VCL_recv, VCL_deliver).<br><br><b>-d</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Daemonize; run <b>varnishlog</b> in the background.<br><br><b>-D</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Stop processing and exit when the Varnish Cache daemon (<b>varnishd</b>) exits.<br><br><b>-E</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Dump raw VSM data in human-readable format. Primarily for debugging Varnish itself.<br><br><b>-f <I>file</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Read shared memory log from the specified file instead of the live VSM.<br><br><b>-g <I>grouping</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the grouping mode for log records. Common values include <I>request</I> (group by request ID), <I>session</I> (group by session ID), and <I>raw</I> (no grouping, show records as they appear).<br><br><b>-h</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display a help message and exit.<br><br><b>-i <I>tag</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Include only log records with the specified tag (e.g., ReqStart, Hit, Miss, VCL_Log). Can be used multiple times.<br><br><b>-I <I>regex</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Include only log records whose content matches the specified regular expression.<br><br><b>-k <I>k-bytes</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the size of the VSM file in kilobytes. Useful when debugging VSM issues.<br><br><b>-L <I>limit</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Limit the number of log lines to process before exiting.<br><br><b>-M <I>regex</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Include only transactions whose request or response details match the specified regular expression.<br><br><b>-n <I>name</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the name of the Varnish instance to connect to. This is useful when multiple Varnish instances are running.<br><br><b>-q <I>query</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify a VSL query expression to filter log records. This allows for complex filtering based on tags, levels, and values.<br><br><b>-r <I>file</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Read log data from a binary file previously created with the <b>-w</b> option.<br><br><b>-R <I>seconds</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Retry connecting to Varnish after a specified number of seconds if the connection is lost.<br><br><b>-S <I>limit</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Maximum number of VSM bytes to skip if the VSM pointer is ahead of the current reading position.<br><br><b>-t <I>seconds</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Timeout for transaction end. If a transaction doesn't end within this time, it's displayed anyway.<br><br><b>-T <I>seconds</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Transaction timeout. If a transaction takes longer than this, it will be considered incomplete and dropped unless <b>-t</b> is also used.<br><br><b>-u</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Unbuffered output. Forces output to be written immediately without buffering.<br><br><b>-v</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Verbose output. Increase verbosity level, showing more detailed information, especially for debugging.<br><br><b>-w <I>file</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Write log data to the specified binary file for later analysis (e.g., with <b>-r</b>).<br><br><b>-x <I>tag</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Exclude log records with the specified tag. Can be used multiple times.<br><br><b>-X <I>regex</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Exclude log records whose content matches the specified regular expression.<br><br><b>-z <I>seconds</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Flush delay. Wait for this many seconds before flushing records for a transaction if it's still active.<br><br>


title: DESCRIPTION
content:
The <b>varnishlog</b> command is a utility within the Varnish Cache suite, designed to provide real-time insight into the operations of a running Varnish instance.<br><br>It reads structured log data directly from Varnish's shared memory (VSM), presenting a continuous stream of events related to client requests, backend fetches, cache hits, cache misses, and various internal Varnish processes. This real-time visibility is invaluable for debugging configuration issues, monitoring performance, understanding caching behavior, and tracking the lifecycle of individual HTTP requests as they pass through the Varnish cache.<br><br><b>varnishlog</b> allows for extensive filtering and grouping of log entries, enabling users to focus on specific types of events, individual client or backend transactions, or even specific VCL actions, making it an indispensable tool for Varnish administrators and developers.


title: CAVEATS
content:
<b>varnishlog</b> requires access to the Varnish Shared Memory (VSM), meaning it needs appropriate permissions to read from the Varnish instance's shared memory segment. If Varnish is not running, or the specified instance name (via <b>-n</b>) is incorrect, <b>varnishlog</b> will not be able to retrieve live log data.<br><br>Without proper filtering, the output can be very verbose, especially on busy Varnish servers, making it difficult to find specific information. It's crucial to utilize filtering options like <b>-i</b>, <b>-x</b>, <b>-q</b>, and grouping options like <b>-g</b>.


title: FILTERING AND GROUPING LOGS
content:
One of <b>varnishlog</b>'s most powerful features is its ability to filter and group log entries. Using options like <b>-g</b> (grouping by request or session), <b>-i</b> (including specific tags), <b>-x</b> (excluding specific tags), and especially <b>-q</b> (VSL query expressions), users can precisely tailor the output to display only relevant information. This is essential for navigating large volumes of log data and quickly identifying patterns or issues.


title: REAL-TIME MONITORING VS. OFFLINE ANALYSIS
content:
While primarily a real-time monitoring tool, <b>varnishlog</b> can also be used for offline analysis. The <b>-w</b> option allows users to write the live log stream to a binary file, which can then be replayed and analyzed later using the <b>-r</b> option. This is useful for capturing specific events or for detailed post-mortem debugging without continuously watching the live stream.


title: HISTORY
content:
<b>varnishlog</b> has been a core component of the Varnish Cache distribution since its early versions. As Varnish Cache evolved, so did <b>varnishlog</b>, gaining more sophisticated filtering capabilities (like VSL query expressions) and output options to help users better understand complex caching behaviors and debug performance issues. Its design to read directly from shared memory reflects Varnish's high-performance architecture, minimizing impact on the main Varnish process.


title: SYNOPSIS
content:
<b>vault</b> [<I>global-options</I>] <I>command</I> [<I>command-specific-options</I>] [<I>arguments</I>]


title: PARAMETERS
content:
<b>-address=<I>address</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the address of the Vault server (e.g., 'http://127.0.0.1:8200'). Can also be set via the VAULT_ADDR environment variable.<br><br><b>-token=<I>token</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the Vault authentication token to use. Can also be set via the VAULT_TOKEN environment variable.<br><br><b>-namespace=<I>namespace</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the target namespace for the operation. Applicable in Vault Enterprise with Namespaces enabled. Can also be set via the VAULT_NAMESPACE environment variable.<br><br><b>-format=<I>format</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Configures the output format for responses. Common formats include 'table' (default), 'json', and 'yaml'.<br><br><b>-no-color</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Disables colorized output in the terminal.<br><br><b>-output-curl-string</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Prints the equivalent <code>curl</code> command string that the <code>vault</code> command would execute against the Vault API, instead of executing the command.<br><br><b>-skip-verify</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Do not verify TLS certificates. This is insecure and should only be used for development or testing.<br><br><b>-help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Shows help for the command or subcommand.<br><br>


title: DESCRIPTION
content:
The <b>vault</b> command-line interface (CLI) provides a unified way to interact with the HashiCorp Vault server. Vault is a powerful tool designed to securely store, manage, and access sensitive data such as API keys, passwords, certificates, and encryption keys.<br><br>It addresses the challenges of secrets management by offering a central, highly available, and auditable system. Vault can dynamically generate secrets on demand, reducing the attack surface by minimizing the lifetime of credentials. It supports various authentication methods and secret engines, allowing integration with diverse systems like databases, cloud providers (AWS, Azure, GCP), and container orchestrators (Kubernetes).<br><br>Through the CLI, users and automated systems can perform essential operations such as initializing and unsealing the Vault server, configuring authentication methods and secret engines, writing and reading secrets, managing policies, and revoking access. It's an indispensable tool in modern DevOps and security workflows.


title: CAVEATS
content:
The <b>vault</b> command is the command-line client for HashiCorp Vault, not a built-in Linux utility; it must be installed separately. It requires a running Vault server instance to function properly, either locally or remotely. Many operations require prior authentication and appropriate policies (permissions) to be granted. Incorrect configuration or use of options like <code>-skip-verify</code> can compromise security.


title: KEY CONCEPTS
content:
Understanding Vault involves several core concepts:<br><b>Secrets Engines</b>: Interfaces that Vault uses to store, generate, or encrypt data. Examples include 'kv' (key-value store), 'pki' (PKI certificate generation), 'aws' (dynamic AWS credentials), and 'database' (dynamic database credentials).<br><b>Auth Methods</b>: Ways for users or machines to authenticate with Vault. Common methods are 'token', 'userpass', 'ldap', 'github', 'kubernetes', and 'AWS IAM'.<br><b>Policies</b>: JSON-based documents that define permissions (what a user or machine can do) within Vault.<br><b>Initialization & Unsealing</b>: For security, Vault starts in a 'sealed' state. It must be initialized once (creating initial keys) and then unsealed on every startup (providing enough master keys to decrypt its data).


title: ENVIRONMENT VARIABLES
content:
The <b>vault</b> CLI client supports several environment variables that can simplify its use and avoid repetitive typing of global options:<br><b>VAULT_ADDR</b>: Sets the default Vault server address.<br><b>VAULT_TOKEN</b>: Provides the default authentication token.<br><b>VAULT_NAMESPACE</b>: Specifies the default target namespace.<br><b>VAULT_SKIP_VERIFY</b>: Equivalent to <code>-skip-verify</code> for TLS.<br><b>VAULT_FORMAT</b>: Sets the default output format.


title: HISTORY
content:
HashiCorp Vault was first publicly released in 2015 by HashiCorp, a company known for infrastructure automation tools. It was developed to address the critical need for a centralized, secure system to manage secrets in dynamic, distributed environments, a problem exacerbated by the rise of cloud computing and microservices architectures. Since its inception, Vault has seen continuous development, adding numerous secret engines, authentication methods, and enterprise features, establishing itself as a leading solution for secrets management and identity-based security.


title: PARAMETERS
content:
<b><b>-q</b>, <b>--quiet</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppresses all standard output, useful for scripting where only the exit status matters.<br><br><b><b>-l</b>, <b>--lrmi</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces <i>vbetool</i> to use the <i>lrmi</i> (Linux Real Mode Interface) module for real mode access. This might be necessary on some systems if direct kernel support is not available or preferred.<br><br><b><b>-p</b>, <b>--ports</b> <i>RANGE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a comma-separated list of I/O port ranges to use. This is an advanced option typically not needed.<br><br><b><b>vbeinfo</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays detailed information about the VESA BIOS Extensions capabilities of the graphics card, including supported modes, memory, and OEM strings.<br><br><b><b>dpms</b> {<b>on</b>|<b>off</b>|<b>standby</b>|<b>suspend</b>}</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Controls the DPMS (Display Power Management Signaling) state of the display. Allows turning the monitor on/off or putting it into low-power states.<br><br><b><b>vbesave</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Saves the current VBE state to an internal buffer. This can be used in conjunction with <b>vberestore</b> to preserve and later restore display settings.<br><br><b><b>vberestore</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Restores a previously saved VBE state. Useful for returning to a known display configuration after temporary changes.<br><br><b><b>vbesetmode</b> <i>MODE_NUMBER</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the display to the specified VESA mode number. Mode numbers can be found using <b>vbeinfo</b> or <b>vbeprobe</b>. For example, <b>vbesetmode 0x118</b> might set 1024x768x16.<br><br><b><b>vbegetmode</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Retrieves and displays the VESA mode number that the display is currently set to.<br><br><b><b>vbeprobe</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Probes and lists available VESA video modes that the graphics card supports, similar to <b>vbeinfo</b> but focused on modes.<br><br>


title: DESCRIPTION
content:
<i>vbetool</i> is a low-level command-line utility designed to interact with the VESA BIOS Extensions (VBE) of a computer's graphics card. VBE provides a standardized interface for software to control display modes, resolutions, and other graphics card features before a full-fledged graphics driver takes over. Typically, <i>vbetool</i> is used during the early boot process, often from an <i>initramfs</i> or similar environment, to set up a specific console resolution for a framebuffer device like <i>uvesafb</i>.<br><br>It operates by executing real-mode VBE calls, which requires access to the system's BIOS and is generally performed with root privileges. This direct hardware manipulation allows for fine-grained control over the display, such as enabling specific video modes, saving and restoring the VBE state, or querying information about the available VBE modes. While modern Linux systems increasingly rely on Kernel Mode Setting (KMS) for display management, <i>vbetool</i> remains valuable for older hardware, specific framebuffer configurations, or troubleshooting scenarios where early graphical output is critical.


title: CAVEATS
content:
<i>vbetool</i> requires root privileges to operate, as it performs direct hardware access. It relies on kernel support for real-mode execution (e.g., via the <i>lrmi</i> module) and may not function correctly on all modern systems, particularly those using UEFI without a Compatibility Support Module (CSM) or with proprietary graphics drivers. Misuse can lead to display issues or system instability.


title: USAGE IN BOOT PROCESS
content:
<i>vbetool</i> is frequently used within the <i>initramfs</i> during the Linux boot sequence. Before the root filesystem is mounted and full graphics drivers are loaded, <i>vbetool</i> can be invoked to set a desired console resolution, providing a graphical boot splash or a higher-resolution text console. This is especially relevant for configurations relying on <i>uvesafb</i>.


title: HISTORY
content:
<i>vbetool</i> emerged in the early days of Linux to provide users with direct control over VESA BIOS Extensions, a standard crucial for setting up console resolutions before advanced graphics drivers were fully loaded or universally available. Its development often paralleled the needs of framebuffer device drivers like <i>vesafb</i> and later <i>uvesafb</i>, which enabled high-resolution graphics on the Linux console. While the advent of Kernel Mode Setting (KMS) has reduced its prominence for general desktop use, <i>vbetool</i> continues to be maintained and used for specific boot-time display configurations, embedded systems, and troubleshooting scenarios.


title: SYNOPSIS
content:
<b>VBoxManage</b> is structured around a vast array of subcommands. The general syntax is:<br><br><b>VBoxManage</b> [<I>global-options</I>] <I>subcommand</I> [<I>subcommand-options</I>] [<I>arguments</I>]<br><br>Examples of subcommands include <I>list</I>, <I>createvm</I>, <I>modifyvm</I>, <I>startvm</I>, <I>controlvm</I>, <I>snapshot</I>, and many more. Each subcommand has its own specific set of options and arguments.


title: PARAMETERS
content:
<b>--version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Displays the VirtualBox version and build information.</i><br><br><b>--help, -h</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Shows the global help message or help for a specific subcommand if followed by the subcommand name.</i><br><br><b>--verbose, -v</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Increases the verbosity of the output, showing more detailed information.</i><br><br><b>--debug</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Enables debug output, useful for troubleshooting internal VirtualBox issues.</i><br><br><b>--nologo</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Suppresses the display of the VirtualBox logo when the command starts.</i><br><br><b>--nocolor</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Disables colored output, which can be useful in terminals that don't support it well.</i><br><br><b>(Subcommand Options)</b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Beyond these global options, <b>VBoxManage</b> operates through a large number of subcommands (e.g., <b>list</b>, <b>createvm</b>, <b>modifyvm</b>, <b>startvm</b>, <b>snapshot</b>, <b>storageattach</b>). Each subcommand has its own extensive set of specific options and arguments. To see options for a specific subcommand, use <b>VBoxManage &lt;subcommand&gt; --help</b>.</i><br><br>


title: DESCRIPTION
content:
<b>VBoxManage</b> is the command-line interface (CLI) for Oracle VM VirtualBox. It allows users to control virtually every aspect of VirtualBox, from creating, configuring, starting, and stopping virtual machines to managing network interfaces, storage devices, snapshots, and global settings. It's an indispensable tool for automation, scripting, and headless server environments where a graphical user interface is not available or desired. With its extensive array of subcommands and options, <b>VBoxManage</b> provides granular control over the entire VirtualBox ecosystem, making it a powerful utility for both casual users and system administrators.


title: CAVEATS
content:
Due to its extensive functionality, <b>VBoxManage</b> can be complex to master, requiring familiarity with numerous subcommands and their specific options. While generally cross-platform, some network or storage operations might have subtle differences or dependencies on the host OS. When running VMs headless, ensure proper resource allocation and network configuration as graphical interaction is not possible.


title: EXTENSIVE SUBCOMMANDS
content:
<i><b>VBoxManage</b>'s power lies in its modular design, with over 50 distinct subcommands covering every aspect of VM management, from basic operations like starting and stopping VMs to advanced features like managing host-only networks, VRDP servers, and storage controllers. Understanding the specific subcommands for your task is key to effective use.</i>


title: SCRIPTING AND AUTOMATION
content:
<i>Given its command-line nature, <b>VBoxManage</b> is exceptionally well-suited for scripting and automating virtual machine operations. This is particularly valuable in CI/CD pipelines, development environments, and server provisioning scenarios where repeatable and unattended VM management is required.</i>


title: HISTORY
content:
Oracle VM VirtualBox, originally developed by Innotek GmbH, was first released in 2007. Sun Microsystems acquired Innotek in 2008, and subsequently, Oracle acquired Sun Microsystems in 2010, continuing the development of VirtualBox. <b>VBoxManage</b> has been a core component of VirtualBox since its early versions, providing the essential command-line interface for managing virtual machines and their environments. Its functionality has continuously expanded with each VirtualBox release to support new features and host/guest operating systems, solidifying its role as a crucial tool for automation and server deployments.


title: SYNOPSIS
content:
<b>VBoxManage clonevm</b> <i>&lt;source_vm_uuid|source_vm_name&gt;</i> <b>--name</b> <i>&lt;new_vm_name&gt;</i> [<br>&nbsp;&nbsp;<b>--groups</b> <i>&lt;group1&gt;</i>[,<i>&lt;group2&gt;</i>...] ] [<br>&nbsp;&nbsp;<b>--basefolder</b> <i>&lt;path&gt;</i> ] [<br>&nbsp;&nbsp;<b>--snapshot</b> <i>&lt;snapshot_uuid|snapshot_name&gt;</i> ] [<br>&nbsp;&nbsp;<b>--mode</b> <i>&lt;mode&gt;</i> ] [<br>&nbsp;&nbsp;<b>--options</b> <i>&lt;option1&gt;</i>[,<i>&lt;option2&gt;</i>...] ] [<br>&nbsp;&nbsp;<b>--uuid</b> <i>&lt;new_vm_uuid&gt;</i> ] [<br>&nbsp;&nbsp;<b>--register</b> ]<br><br><i>&lt;mode&gt;</i>: <b>all</b> | <b>machine</b> (default: <b>all</b>)<br><i>&lt;option&gt;</i>: <b>link</b> | <b>full</b> (default: <b>full</b>), <b>keepnatmacs</b>, <b>keepdisknames</b>, <b>keephwuuids</b>, <b>keepinputoutputcache</b>


title: PARAMETERS
content:
<b><i>&lt;source_vm_uuid|source_vm_name&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The UUID or name of the virtual machine to be cloned.<br><br><b><b>--name</b> <i>&lt;new_vm_name&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the name for the new cloned virtual machine. This is a mandatory option.<br><br><b><b>--groups</b> <i>&lt;group1&gt;</i>[,<i>&lt;group2&gt;</i>...]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assigns the new VM to one or more VirtualBox groups, separated by commas.<br><br><b><b>--basefolder</b> <i>&lt;path&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the path to the directory where the new VM's configuration and disk files will be stored. If omitted, VirtualBox's default VM folder is used.<br><br><b><b>--snapshot</b> <i>&lt;snapshot_uuid|snapshot_name&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Clones the VM from a specific snapshot, rather than its current state. Useful for restoring a previous state as a new VM.<br><br><b><b>--mode</b> <i>&lt;mode&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Defines what components of the VM are cloned. <b>all</b> clones the machine and all attached storage. <b>machine</b> clones only the machine configuration without disk images. Default is <b>all</b>.<br><br><b><b>--options</b> <i>&lt;option1&gt;</i>[,<i>&lt;option2&gt;</i>...]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Controls specific aspects of the cloning process. Key options include:<br>&nbsp;&nbsp;- <b>link</b>: Creates a linked clone (shares base disk, default is <b>full</b>).<br>&nbsp;&nbsp;- <b>full</b>: Creates a full clone (independent copy).<br>&nbsp;&nbsp;- <b>keepnatmacs</b>: Retains the original MAC addresses for NAT network adapters.<br>&nbsp;&nbsp;- <b>keepdisknames</b>: Retains the original disk attachment names.<br>&nbsp;&nbsp;- <b>keephwuuids</b>: Retains the original hardware UUIDs (generally not recommended).<br>&nbsp;&nbsp;- <b>keepinputoutputcache</b>: Retains the original I/O cache settings.<br><br><b><b>--uuid</b> <i>&lt;new_vm_uuid&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a custom UUID for the new cloned VM. If not provided, VirtualBox generates a new unique UUID.<br><br><b><b>--register</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Registers the new cloned VM with VirtualBox (this is the default behavior).<br><br>


title: DESCRIPTION
content:
The <b>VBoxManage clonevm</b> subcommand is a powerful utility within Oracle VM VirtualBox that enables users to create duplicates of existing virtual machines. This functionality is crucial for various use cases, including creating test environments, backing up VMs before major changes, distributing pre-configured systems, or quickly deploying multiple identical instances. It supports two primary cloning modes:<br><b>full clones</b>, which are independent copies including all disk images, and<br><b>linked clones</b>, which share the original VM's disk image but store their own changes in a separate differencing image. The command provides flexibility to specify the new VM's name, UUID, location, and whether to clone from a specific snapshot.


title: CAVEATS
content:
This command is a subcommand of <b>VBoxManage</b>, not a standalone executable. <br>Linked clones inherently depend on the original VM and its base disk image; deleting or moving the parent can break the clone. <br>Full clones require significant disk space equal to the original VM's storage. <br>Be mindful of duplicate network MAC addresses and hardware UUIDs when creating multiple clones, as this can lead to network conflicts or licensing issues for some software. The <code>--keepnatmacs</code> and <code>--keephwuuids</code> options control this behavior.


title: FULL VS. LINKED CLONES
content:
<b>Full clones</b> are entirely independent copies, including all disk images, and can operate without the original VM. They consume more disk space but offer maximum portability. <br><b>Linked clones</b> share the original VM's base disk image and store only their changes in a new differencing disk. They consume less disk space but require the parent VM and its base disk to be present and unchanged for the clone to function.


title: UUID AND MAC ADDRESS HANDLING
content:
By default, <b>VBoxManage clonevm</b> generates new UUIDs and MAC addresses for the cloned VM. This is generally recommended to prevent conflicts on the network or with software licenses. However, specific options like <code>--keepnatmacs</code> and <code>--keephwuuids</code> allow retaining the original values for NAT network interfaces and the hardware UUID respectively, which might be necessary in specific scenarios but should be used with caution.


title: HISTORY
content:
The <code>clonevm</code> feature has been an integral part of Oracle VM VirtualBox's <b>VBoxManage</b> command-line interface since its early versions. It evolved alongside the product, offering more granular control with options like linked/full cloning, snapshot-based cloning, and handling of various hardware identifiers as VirtualBox matured and its user base grew, making VM management more flexible and automated for developers and system administrators.


title: SEE ALSO
content:
VBoxManage(1), VBoxManage createvm(1), VBoxManage import(1), VBoxManage export(1), VBoxManage snapshot(1)


title: SYNOPSIS
content:
<b>vboxmanage-cloud</b> [<i>OPTIONS</i>] <i>&lt;input_disk_image&gt;</i> <i>&lt;output_disk_image&gt;</i>


title: PARAMETERS
content:
<b><i>&lt;input_disk_image&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Path to the existing VirtualBox disk image (e.g., VDI, VMDK) to be cloud-enabled.<br><br><b><i>&lt;output_disk_image&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Path where the new, cloud-init ready disk image will be saved.<br><br><b><b>--user-data</b> <i>FILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the path to a file containing cloud-init user-data to be injected.<br><br><b><b>--meta-data</b> <i>FILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the path to a file containing cloud-init meta-data to be injected.<br><br><b><b>--network-config</b> <i>FILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the path to a file containing cloud-init network configuration.<br><br><b><b>--force</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Overwrites the <i>&lt;output_disk_image&gt;</i> if it already exists.<br><br><b><b>--iso-path</b> <i>PATH</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Optional path to save the generated cloud-init ISO file, if one is used internally.<br><br><b><b>--vm-name</b> <i>NAME</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Optional name for any temporary VirtualBox VM created during the process.<br><br><b><b>--memory</b> <i>MB</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Optional memory allocation (in MB) for any temporary VirtualBox VM.<br><br><b><b>--cpus</b> <i>N</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Optional number of CPUs for any temporary VirtualBox VM.<br><br><b><b>--output-format</b> <i>FORMAT</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Optional output disk image format (e.g., VDI, VMDK, RAW).<br><br>


title: DESCRIPTION
content:
The <b>vboxmanage-cloud</b> command is typically a project-specific or custom script designed to facilitate the integration of VirtualBox virtual machines with <i>cloud-init</i>, a widely used cross-platform cloud instance initialization system. Unlike standard <b>VBoxManage</b> subcommands, <b>vboxmanage-cloud</b> is not a universally provided utility but rather a wrapper or conceptual tool often found in development, testing, or specific automation environments (e.g., OpenStack DevStack, Vagrant setups).<br><br>Its primary purpose is to prepare a VirtualBox disk image (e.g., VDI or VMDK) so that a VM created from it can be automatically configured upon its first boot by cloud-init. This usually involves injecting or associating cloud-init configuration data such as user-data, meta-data, and network-config with the disk image. The underlying mechanism often involves creating a temporary VirtualBox VM, attaching a cloud-init generated ISO containing the configuration, and then exporting a new, 'cloud-ready' disk image, streamlining the process of creating self-provisioning VirtualBox instances.


title: CAVEATS
content:
The <b>vboxmanage-cloud</b> command is <i>not</i> a standard, universally available utility provided by Oracle VirtualBox itself. It typically refers to a custom script or a component within specific project environments (like OpenStack's DevStack or specialized cloud-image tools) that leverages <b>VBoxManage</b> and <b>cloud-init</b> functionalities. Therefore, its exact syntax, available options, and behavior can vary significantly depending on the specific implementation it comes from. Users should consult the documentation or source code of the project that provides this particular script.


title: TYPICAL USAGE
content:
This command is commonly used to take a clean, generic VirtualBox OS image and transform it into a self-configuring instance suitable for automated deployments, similar to how cloud images are consumed in AWS, OpenStack, or Azure. It's particularly useful for local development and testing cycles where quickly spinning up configured VMs is crucial.


title: UNDERLYING MECHANISM
content:
While implementations vary, a common approach involves <b>vboxmanage-cloud</b> internally using <b>VBoxManage</b> to create a temporary VM from the input disk. It then utilizes <b>cloud-localds</b> (or a similar tool) to generate an ISO image containing the cloud-init data, attaches this ISO to the temporary VM, and boots it. Cloud-init inside the VM reads the configuration. After successful provisioning (or after a set time), the temporary VM is shut down, and its modified disk (or a snapshot of it) is exported as the output image.


title: HISTORY
content:
The concept behind <b>vboxmanage-cloud</b> emerged from the increasing need to automate the provisioning of virtual machines in local development and testing environments using VirtualBox, mirroring the behavior of VMs in public cloud platforms. As <i>cloud-init</i> became the de-facto standard for cloud instance initialization, developers sought ways to easily inject cloud-init configuration into VirtualBox images. Rather than a formally developed command, <b>vboxmanage-cloud</b> typically represents a community-driven or project-specific effort to script this integration, often appearing in projects like OpenStack DevStack for local testing of cloud images, or within Vagrant box creation workflows.


title: SYNOPSIS
content:
<b>VBoxManage controlvm</b> <I>&lt;uuid|vmname&gt;</I> <I>&lt;action&gt;</I> [<I>&lt;action_parameters&gt;</I>]<br><br>Examples:<br><b>VBoxManage controlvm</b> "MyVM" <b>poweroff</b><br><b>VBoxManage controlvm</b> "UbuntuServer" <b>savestate</b><br><b>VBoxManage controlvm</b> "Win10Dev" <b>keyboardputtext</b> "Hello World"


title: PARAMETERS
content:
<b>poweroff</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Immediately powers off the VM, similar to unplugging a physical machine. This can lead to data loss.<br><br><b>reset</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Resets the VM, akin to pressing the reset button on a physical computer.<br><br><b>savestate</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Saves the current running state of the VM to disk, allowing it to be resumed exactly where it left off.<br><br><b>pause</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Temporarily suspends the execution of the VM. The VM's state remains in memory.<br><br><b>resume</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Resumes a previously paused VM from its suspended state.<br><br><b>acpipowerbutton</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sends an ACPI power button event to the VM. This typically triggers a graceful shutdown if the guest OS supports ACPI.<br><br><b>acpisleepbutton</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sends an ACPI sleep button event to the VM, initiating a sleep or suspend state if supported by the guest.<br><br><b>keyboardputtext <text></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Injects the specified text as keyboard input into the guest OS. Useful for automated logins or commands.<br><br><b>guestmemoryballoon <megabytes></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Adjusts the guest memory balloon size, dynamically allocating or deallocating RAM for the guest VM. Requires Guest Additions.<br><br><b>vrde <on|off|config|...></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Controls the VirtualBox Remote Desktop Extension (VRDE) for the VM, allowing remote access. Has various sub-options for configuration.<br><br>


title: DESCRIPTION
content:
The <I>VBoxManage controlvm</I> command is a crucial utility within the Oracle VirtualBox command-line interface, providing granular control over running virtual machines. It allows users to manage a VM's lifecycle, change its operational state, and interact with the guest system directly from the host command line. This command is indispensable for automating VM operations, scripting complex virtualized environments, and managing headless VMs without direct GUI interaction. It can power on/off, pause, reset, save the state of a VM, or even send specific events like ACPI power signals to facilitate graceful shutdowns. Its versatility makes it a cornerstone for system administrators and developers working with VirtualBox.


title: CAVEATS
content:
Using <I>poweroff</I> can lead to data corruption or loss in the guest OS, as it does not allow for a graceful shutdown. Prefer <I>acpipowerbutton</I> for clean shutdowns.<br>Many commands require the VirtualBox Guest Additions to be installed in the guest OS for full functionality (e.g., <I>acpipowerbutton</I>, <I>guestmemoryballoon</I>).<br>The VM must be in an appropriate state for certain commands; for example, you cannot <I>resume</I> a VM that is not <I>paused</I>.


title: AUTOMATION AND SCRIPTING
content:
<I>controlvm</I> is foundational for automating VM lifecycle management in scripts, allowing for unattended operations like scheduled shutdowns, reboots, or state saving.


title: HEADLESS OPERATIONS
content:
It is crucial for managing "headless" VMs (VMs running without a graphical user interface), common in server environments or CI/CD pipelines, where all interactions are via the command line.


title: HISTORY
content:
The <I>VBoxManage</I> command, including its <I>controlvm</I> subcommand, has been an integral part of VirtualBox since its early days. VirtualBox was originally developed by Innotek GmbH, then acquired by Sun Microsystems in 2008, and subsequently by Oracle Corporation in 2010. Throughout these transitions, <I>VBoxManage</I> has remained the primary command-line interface for managing and controlling VirtualBox virtual machines, consistently evolving to support new features and functionalities.


title: SEE ALSO
content:
VBoxManage(1), VBoxManage startvm(1), VBoxManage showvminfo(1), VBoxManage modifyvm(1), VBoxManage snapshot(1)


title: SYNOPSIS
content:
<b>vboxmanage createvm</b> <b>--name</b> <i>&lt;name&gt;</i> <b>--ostype</b> <i>&lt;ostype&gt;</i> [<br>&nbsp;&nbsp;&nbsp;&nbsp;[<b>--uuid</b> <i>&lt;uuid&gt;</i>]<br>&nbsp;&nbsp;&nbsp;&nbsp;[<b>--group</b> <i>&lt;group&gt;</i>]<br>&nbsp;&nbsp;&nbsp;&nbsp;[<b>--basefolder</b> <i>&lt;folder&gt;</i>]<br>&nbsp;&nbsp;&nbsp;&nbsp;[<b>--register</b> | <b>--unregister</b>]<br>&nbsp;&nbsp;&nbsp;&nbsp;[<b>--default</b>]]


title: PARAMETERS
content:
<b><b>--name</b> <i>&lt;name&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>(Mandatory)</i> Specifies the name of the new virtual machine. This name must be unique among all registered VMs.<br><br><b><b>--ostype</b> <i>&lt;ostype&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>(Mandatory)</i> Defines the operating system type for the VM. This helps VirtualBox set optimal default settings for the virtual hardware. Use <b>vboxmanage list ostypes</b> to see a list of valid types.<br><br><b><b>--uuid</b> <i>&lt;uuid&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assigns a specific UUID to the VM instead of generating a random one. UUIDs are unique identifiers for VMs.<br><br><b><b>--group</b> <i>&lt;group&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assigns the new VM to a logical group. Groups help organize multiple VMs in the VirtualBox Manager.<br><br><b><b>--basefolder</b> <i>&lt;folder&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the absolute path to the directory where the VM's configuration file and associated data will be stored. If not specified, VirtualBox's default VM folder is used.<br><br><b><b>--register</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>(Default behavior)</i> Registers the newly created VM with VirtualBox, making it visible in the VirtualBox Manager and accessible via other <b>vboxmanage</b> commands.<br><br><b><b>--unregister</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Creates the VM configuration file but does <i>not</i> register it with VirtualBox. This can be useful if you plan to move or copy the VM before registering it manually.<br><br><b><b>--default</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Marks this VM as the default machine (less commonly used with <b>createvm</b>).<br><br>


title: DESCRIPTION
content:
The <b>vboxmanage createvm</b> command is a fundamental tool within Oracle VirtualBox for setting up a new virtual machine (VM) definition. It creates the necessary configuration file (<i>.vbox</i> file) for a VM, establishing its basic properties such as its name, operating system type, and storage location. This command does <i>not</i> create a virtual hard disk or install an operating system; it merely prepares the virtual machine's empty shell. After creating the VM, you would typically use other <b>vboxmanage</b> commands like <b>modifyvm</b> to configure its hardware (e.g., RAM, CPU, network adapters) and <b>createmedium disk</b> or <b>storageattach</b> to connect virtual hard disks. The <b>createvm</b> command is the initial step in a multi-step process to deploy a fully functional virtual machine.


title: CAVEATS
content:
This command only creates the VM definition; it does <i>not</i> automatically create a virtual hard disk or install an operating system.<br>The <b>--name</b> provided must be unique among all registered VirtualBox VMs.<br>The <b>--ostype</b> parameter requires a valid OS type string, which can be found by running <b>vboxmanage list ostypes</b>. Using an incorrect or misspelled OS type will result in an error.


title: FINDING OS TYPES
content:
To get a comprehensive list of supported operating system types for the <b>--ostype</b> parameter, run the command <i>vboxmanage list ostypes</i>. This output provides the <i>ID</i> string needed for the command.


title: NEXT STEPS AFTER CREATION
content:
After executing <b>createvm</b>, the VM is an empty shell. You will typically need to perform the following steps:<br>    - <b>Configure Hardware:</b> Use <i>vboxmanage modifyvm</i> to adjust RAM, CPU cores, video memory, and other settings.<br>    - <b>Attach Storage:</b> Use <i>vboxmanage createmedium disk</i> to create a new virtual hard disk, and then <i>vboxmanage storagectl</i> and <i>vboxmanage storageattach</i> to attach it and an optical drive (for an ISO installer) to the VM.<br>    - <b>Install OS:</b> Start the VM and proceed with the operating system installation.


title: HISTORY
content:
The <b>vboxmanage</b> command-line interface, including <b>createvm</b>, has been a core component of VirtualBox since its early development by Innotek GmbH. VirtualBox was first released in 2007. After Innotek was acquired by Sun Microsystems in 2008, and then Sun by Oracle Corporation in 2010, <b>vboxmanage</b> continued to evolve as the primary tool for scripting and automating VirtualBox operations on headless servers or for advanced users. The <b>createvm</b> subcommand has consistently provided a programmatic way to initialize new virtual machine configurations, reflecting the need for automation in virtualized environments.


title: SEE ALSO
content:
vboxmanage list vms, vboxmanage modifyvm, vboxmanage registervm, vboxmanage unregistervm, vboxmanage storageattach, vboxmanage createmedium disk, vboxmanage showvminfo


title: SYNOPSIS
content:
<b>vboxmanage</b> <i>export</i> &lt;<i>vmname|uuid</i>&gt; <b>--output</b> &lt;<i>filename.ovf|.ova</i>&gt; [<i>options</i>]


title: PARAMETERS
content:
<b>&lt;vmname|uuid&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the name or unique identifier (UUID) of the virtual machine to be exported.<br><br><b><b>--output</b> &lt;<i>filename.ovf|.ova</i>&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Defines the full path and name for the output file. The extension must be either <i>.ovf</i> (for an OVF directory structure) or <i>.ova</i> (for a single OVF archive file).<br><br><b><b>--ovf20</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Exports the VM using the OVF 2.0 standard instead of the default OVF 1.0. This may offer better compatibility with newer virtualization software.<br><br><b><b>--manifest</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Includes a manifest file (<i>.mf</i>) in the exported OVF package. This file contains SHA-1 checksums of all other files in the package, allowing for integrity verification upon import.<br><br><b><b>--preserve-mac-addresses</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Instructs VirtualBox to retain the MAC addresses of the virtual machine's network adapters in the exported package. By default, new MAC addresses are generated upon import to avoid conflicts.<br><br><b><b>--dry-run</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Performs a simulated export without actually writing any files. This is useful for checking if the command syntax is correct and if there are any potential issues before committing to a full export.<br><br><b><b>--product</b> &lt;<i>name</i>&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the product name metadata within the OVF package, providing identification for the exported VM.<br><br><b><b>--vendor</b> &lt;<i>name</i>&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the vendor name metadata within the OVF package, indicating the creator or provider of the VM.<br><br><b><b>--version</b> &lt;<i>version</i>&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets a version string metadata for the exported VM, useful for tracking different iterations or releases.<br><br><b><b>--description</b> &lt;<i>text</i>&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Adds a custom descriptive text to the OVF package, providing more detailed information about the virtual machine.<br><br>


title: DESCRIPTION
content:
The <b>vboxmanage export</b> command facilitates the creation of a portable package for a VirtualBox virtual machine. This package, typically in Open Virtualization Format (OVF) or its archive variant (OVA), encapsulates the virtual machine's configuration, disk images, and other associated files into a single, standardized bundle. This is highly useful for several purposes: <br><br><i>Backup:</i> Creating a complete snapshot of a VM for disaster recovery. <br><i>Sharing:</i> Distributing a pre-configured VM to other users or systems. <br><i>Migration:</i> Moving a VM from one VirtualBox host to another, or even to other virtualization platforms that support OVF/OVA, such as VMware vSphere or KVM (with proper conversion utilities). <br><br>The command allows specifying metadata like product, vendor, and version, making the exported package more informative. It ensures that the VM's state, as of the export time, is preserved for later re-importation.


title: CAVEATS
content:
Exporting a virtual machine can consume significant disk space, as the output file includes all virtual disk images. <br><br>For a consistent export, especially for production VMs, it is highly recommended to power off the virtual machine before exporting. Exporting a running or saved-state VM might lead to inconsistencies or issues upon import into different environments. <br><br>While OVF/OVA is a standard, perfect compatibility between different virtualization platforms is not always guaranteed. Some features or settings might not translate perfectly when imported into a non-VirtualBox hypervisor.


title: OVF VS. OVA
content:
The <i>Open Virtualization Format (OVF)</i> is a directory containing multiple files: an XML descriptor file (<i>.ovf</i>), virtual disk files (<i>.vmdk</i>, <i>.vdi</i>, etc.), manifest (<i>.mf</i>), and certificates (<i>.cert</i>). The <i>Open Virtualization Appliance (OVA)</i> is a single file archive (a TAR archive) that bundles all these OVF components together. OVA is generally preferred for simpler distribution and sharing, while OVF allows for easier inspection of individual components.


title: EXPORTED CONTENT
content:
When a VM is exported, the OVF/OVA package typically includes:<br><i>Virtual Machine Configuration:</i> CPU, RAM, network adapters, storage controllers, etc.<br><i>Virtual Disk Images:</i> The actual data disks associated with the VM.<br><i>Metadata:</i> Information such as product name, vendor, version, and description.<br><i>Snapshots:</i> Note that only the current state of the VM (including its base disk and any merged snapshot data) is exported, not individual snapshot branches for independent restoration.


title: HISTORY
content:
The `vboxmanage` command-line utility is an integral part of Oracle VM VirtualBox, a virtualization product originally developed by Innotek GmbH, later acquired by Sun Microsystems, and then by Oracle Corporation. The `export` functionality has been a fundamental feature of VirtualBox since its early versions, providing a robust mechanism for VM portability and distribution, aligning with the growing need for standardized virtualization formats like OVF/OVA.


title: SYNOPSIS
content:
<b>VBoxManage extpack</b> <br><br>Commands:<br><i>install</i> &lt;filename&gt; [--replace]<br><i>uninstall</i> &lt;name&gt; [--force]<br><i>list</i>


title: PARAMETERS
content:
<b><b>install</b> <filename></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Installs an extension pack from the specified <i>.vbox-extpack</i> file.<br><br><b>--replace</b><br>&nbsp;&nbsp;&nbsp;&nbsp;(Optional) Used with <b>install</b>, this option replaces an existing extension pack if it's already installed. Useful for upgrading or reinstalling.<br><br><b><b>uninstall</b> <name></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Uninstalls the specified extension pack by its unique name (e.g., 'Oracle VM VirtualBox Extension Pack').<br><br><b>--force</b><br>&nbsp;&nbsp;&nbsp;&nbsp;(Optional) Used with <b>uninstall</b>, this option forces the uninstallation, ignoring some checks or warnings.<br><br><b><b>list</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a list of all currently installed VirtualBox Extension Packs, including their versions and descriptions.<br><br>


title: DESCRIPTION
content:
The `VBoxManage extpack` command is a crucial utility within the VirtualBox command-line interface, designed specifically for managing VirtualBox Extension Packs. These packs provide additional functionality to VirtualBox, such as USB 2.0/3.0 support, Host webcam pass-through, Intel PXE boot ROM, and disk encryption. This command allows users to <i>install</i> new extension packs, <i>list</i> currently installed ones, and <i>uninstall</i> existing packs, enabling customization and enhancement of VirtualBox's capabilities from the terminal. It is an essential tool for headless server environments or for automating VirtualBox deployments and configurations.


title: CAVEATS
content:
<b>Licensing:</b> The Oracle VM VirtualBox Extension Pack often has a different license (e.g., Personal Use and Evaluation License - PUEL) than VirtualBox itself (GPLv3). Users must review and accept these terms during installation.<br><br><b>Privileges:</b> Installing or uninstalling extension packs typically requires administrator (root on Linux/macOS, elevated on Windows) privileges.<br><br><b>Version Compatibility:</b> Extension packs are usually tied to specific VirtualBox versions. An extension pack designed for an older version might not work correctly or install on a newer VirtualBox release, and vice versa.


title: DOWNLOADING EXTENSION PACKS
content:
Extension packs are typically downloaded as <i>.vbox-extpack</i> files from the official VirtualBox website (www.virtualbox.org). It's crucial to download the version that exactly matches your installed VirtualBox version.


title: SILENT INSTALLATION
content:
For automated scripts, you can use the <i>--replace</i> option with <b>install</b> and pipe 'yes' to standard input to automatically accept the license agreement. Example: <i>echo yes | VBoxManage extpack install --replace "/path/to/pack.vbox-extpack"</i>


title: HISTORY
content:
VirtualBox Extension Packs were introduced early in VirtualBox's development (around version 4.0 or earlier) to modularize certain features, particularly those with different licensing terms or external dependencies (like USB 2.0/3.0). This allowed the core VirtualBox product to remain open-source (GPL) while offering additional proprietary or differently licensed functionalities through separate, installable packages. The `extpack` subcommand was consequently integrated into `VBoxManage` to provide a robust command-line method for managing these essential add-ons, reflecting VirtualBox's evolution towards a more flexible and extensible architecture.


title: SYNOPSIS
content:
<b>VBoxManage import</b> <i>&lt;ovf-file&gt;</i> [<br>&nbsp;&nbsp;<b>--dry-run</b><br>&nbsp;&nbsp;<b>--options</b> <i>&lt;option-list&gt;</i><br>&nbsp;&nbsp;<b>--vsys</b> <i>&lt;number&gt;</i>|<b>all</b><br>&nbsp;&nbsp;<b>--settingsfile</b> <i>&lt;filename&gt;</i><br>&nbsp;&nbsp;<b>--preserve-mac-addresses</b><br>&nbsp;&nbsp;<b>--basefolder</b> <i>&lt;folder&gt;</i><br>&nbsp;&nbsp;<b>--vmname</b> <i>&lt;name&gt;</i><br>&nbsp;&nbsp;<b>--groups</b> <i>&lt;group1&gt;,...</i><br>&nbsp;&nbsp;<b>--cpus</b> <i>&lt;number&gt;</i><br>&nbsp;&nbsp;<b>--memory</b> <i>&lt;MB&gt;</i><br>&nbsp;&nbsp;<b>--vram</b> <i>&lt;MB&gt;</i><br>&nbsp;&nbsp;<b>--accelerate-vram</b> <i>&lt;on|off&gt;</i><br>&nbsp;&nbsp;<b>--eula accept</b><br>&nbsp;&nbsp;<i>(and many other VM configuration options)</i><br>]


title: PARAMETERS
content:
<b><i>&lt;ovf-file&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The path to the OVF descriptor file or the OVA appliance file to be imported.<br><br><b><b>--dry-run</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Performs a simulation of the import process without actually importing the VM. It prints the proposed settings and any options that can be used to customize the import, useful for generating a <b>--settingsfile</b> or <b>--options</b> list.<br><br><b><b>--options</b> <i>&lt;option-list&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a comma-separated list of options for the import process. These options are typically generated by a <b>--dry-run</b> and allow fine-grained control over the imported VM's settings, such as network adapters or CPU features.<br><br><b><b>--vsys</b> <i>&lt;number&gt;</i>|<b>all</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Imports a specific virtual system (VM) from a multi-VM OVF package or all of them. Use <b>vboxmanage import &lt;ovf-file&gt; --dry-run</b> to see available <i>vsys</i> numbers if the OVF contains multiple virtual machines.<br><br><b><b>--settingsfile</b> <i>&lt;filename&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Imports settings from a specified file. This file can be generated by a <b>--dry-run</b> operation and then modified to customize the import process. It's an alternative to specifying all options on the command line.<br><br><b><b>--preserve-mac-addresses</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Keeps the original MAC addresses of the network adapters as defined in the OVF/OVA. By default, VirtualBox generates new MAC addresses during import to avoid conflicts.<br><br><b><b>--basefolder</b> <i>&lt;folder&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the absolute path to the folder where the imported VM's files (e.g., .vbox file, virtual disk images) will be stored. If not specified, the default VirtualBox Machines folder is used.<br><br><b><b>--vmname</b> <i>&lt;name&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assigns a specific name to the imported virtual machine. If not provided, VirtualBox uses the name defined in the OVF descriptor.<br><br><b><b>--groups</b> <i>&lt;group1&gt;,...</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assigns the imported virtual machine to one or more VirtualBox groups (e.g., 'Servers', 'Development') for better organization within the VirtualBox Manager.<br><br><b><b>--cpus</b> <i>&lt;number&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Overrides the number of virtual CPUs specified in the OVF descriptor for the imported VM. This allows adjusting the CPU allocation to match host resources or specific requirements.<br><br><b><b>--memory</b> <i>&lt;MB&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Overrides the amount of base memory (RAM) in megabytes specified in the OVF descriptor for the imported VM. Useful for tuning performance based on host memory availability.<br><br><b><b>--eula accept</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Automatically accepts the End-User License Agreement (EULA) if one is embedded in the OVF/OVA package. This is required for some appliances, and without it, the import process will fail.<br><br><b><b>--nic&lt;1-N&gt;</b> <i>&lt;type&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the network attachment type for a specific network adapter (e.g., <b>nat</b>, <b>bridged</b>, <b>hostonly</b>), overriding the OVF settings.<br><br><b><b>--unit</b> <i>&lt;device-id&gt;</i> <b>--disk</b> <i>&lt;filename&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Allows specifying a new path for a virtual disk image when importing. This is useful if the disk paths in the OVF are incorrect or you want to relocate them to a specific storage location.<br><br>


title: DESCRIPTION
content:
The <b>vboxmanage import</b> command is a crucial utility within Oracle VirtualBox that allows users to import virtual machines from pre-packaged appliance files, typically in the Open Virtualization Format (OVF) or its archive counterpart, OVA (Open Virtual Appliance). OVF is a standardized, open-source, and portable format for packaging and distributing virtual machines, enabling interoperability between various virtualization platforms. An OVA file is essentially a single-file archive containing the OVF descriptor XML file, manifest, certificate, and all associated virtual disk images (VMDK, VDI, etc.).<br><br>When you use <b>vboxmanage import</b>, VirtualBox reads the OVF descriptor to understand the virtual machine's configuration, including CPU, RAM, network adapters, disk images, and other hardware settings, then creates a new virtual machine definition and copies the disk images into the specified or default VirtualBox machine folder. This command is indispensable for deploying pre-built virtual appliances, sharing VMs, or migrating them from other virtualization software that supports the OVF standard. It streamlines the process of getting a complex virtual environment up and running with minimal manual configuration.


title: CAVEATS
content:
<b>Disk Space:</b> Ensure sufficient disk space on the host machine for the imported virtual disks, which can be significantly larger than the compressed OVA file.<br><br><b>Hardware Compatibility:</b> The imported VM's hardware configuration (e.g., CPU features, chipsets) might not be fully compatible with your host system, potentially requiring adjustments after import.<br><br><b>Network Configuration:</b> Network settings (e.g., NAT, Bridged, Host-Only) defined in the OVF may not match your host's network environment and often need manual adjustment post-import.<br><br><b>Guest Additions:</b> VirtualBox Guest Additions might not be installed or be outdated in the imported VM, which can affect performance and host-guest integration (e.g., clipboard, drag-and-drop, screen resolution). It's often recommended to update or install them after import.<br><br><b>EULA:</b> Some appliances require explicit acceptance of an End-User License Agreement using the <b>--eula accept</b> option; otherwise, the import will fail.


title: INSPECTING OVF/OVA CONTENT
content:
An OVA file is essentially a TAR archive. You can inspect its contents using `tar -tf <file.ova>` to see the `.ovf` descriptor file and associated `.vmdk`/`.vdi` disk images. The `.ovf` file itself is an XML document that precisely details the virtual machine's configuration and properties.


title: MODIFYING SETTINGS POST-IMPORT
content:
While <b>vboxmanage import</b> allows some configuration overrides during the import process, extensive customization (e.g., adding more virtual disks, configuring specific port forwarding rules, changing storage controllers) is often best done after the initial import using the <b>vboxmanage modifyvm</b> command or through the VirtualBox GUI.


title: OVF PROPERTIES
content:
Some OVF files include defined properties that can be configured during import. These properties are often presented as 'options' during a <b>--dry-run</b> and can be passed as key-value pairs via the <b>--options</b> parameter, allowing for further customization of the appliance at deployment time.


title: HISTORY
content:
The Open Virtualization Format (OVF) standard was developed by the Distributed Management Task Force (DMTF) and initially published around 2007. VirtualBox began supporting OVF/OVA import and export capabilities in its early 2.x versions (e.g., VirtualBox 2.2, released in 2009, significantly improved OVF support), making it a long-standing core feature for VM portability and distribution. Its continuous development reflects the growing need for interoperability between virtualization platforms.


title: SEE ALSO
content:
vboxmanage export(1), vboxmanage createvm(1), vboxmanage registervm(1), vboxmanage modifyvm(1), vboxmanage list vms(1)


title: SYNOPSIS
content:
<b>VBoxManage list <I>object_type</I> [options]</b><br><br>Where <b><I>object_type</I></b> specifies the category of VirtualBox entities to list, and <b>[options]</b> provides modifiers for the output.


title: PARAMETERS
content:
<b><b><I>object_type</I></b>:</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the type of VirtualBox entity to list. Common types include:<br><b>vms</b>: All registered virtual machines.<br><b>runningvms</b>: Only virtual machines currently running.<br><b>harddisks</b>: Registered virtual disk images.<br><b>dvds</b>: Registered DVD images.<br><b>floppies</b>: Registered floppy images.<br><b>hostonlyifs</b>: Host-only network interfaces.<br><b>bridgedifs</b>: Bridged network interfaces.<br><b>dhcpservers</b>: DHCP servers configured for NAT networks or host-only networks.<br><b>natrules</b>: NAT rules for NAT networks.<br><b>usbhost</b>: USB devices connected to the host.<br><b>usbfs</b>: USB filters for virtual machines.<br><b>extpacks</b>: Installed extension packs.<br><b>guestos</b>: Supported guest operating system types.<br><b>hostinfo</b>: Information about the host system.<br><b>hostdvds</b>: Host DVD drives.<br><b>hostfloppies</b>: Host floppy drives.<br><br><b><b>--details</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays more comprehensive information for the specified <i>object_type</i>. This option is particularly useful for getting verbose details about VMs, hard disks, or network interfaces.<br><br><b><b>--long</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Similar to <b>--details</b>, often providing an extensive, multi-line format of information, especially useful when listing VMs.<br><br>


title: DESCRIPTION
content:
<i>VBoxManage</i> is the powerful command-line interface for Oracle VM VirtualBox, enabling comprehensive control and management of all aspects of the virtualization platform. The <b><I>VBoxManage list</I></b> command is a fundamental subcommand within <i>VBoxManage</i>, designed to query and display detailed information about various VirtualBox entities and configurations.<br><br>It serves as a crucial tool for both administrators and automation scripts, providing a programmatic way to retrieve current states and configurations without needing to interact with the graphical user interface. Users can list virtual machines, hard disk images, network interfaces (host-only, bridged), USB devices, installed extension packs, supported guest operating systems, and host system information. The output can range from concise summaries to extensive detailed reports, depending on the specific entity queried and the options used, making it highly versatile for diagnostics, inventory management, and scripting complex VirtualBox operations.


title: CAVEATS
content:
The output format of <b><I>VBoxManage list</I></b> can sometimes be extensive and may require piping to tools like <i>grep</i>, <i>awk</i>, or <i>less</i> for effective filtering and viewing. While generally stable, minor variations in output format can occur between VirtualBox versions, which might affect scripts relying on precise parsing.<br>Administrative privileges might be required for certain listings depending on the host operating system and VirtualBox installation.


title: PARAMETERS
content:
<b><i>&lt;uuid|name&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The unique identifier (UUID) or the registered name of the virtual machine to be moved.<br><br><b><b>--target-folder</b> <i>&lt;folder&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the absolute path to the new directory where the VM's files should be relocated. This directory must exist and be writable by the user running the command.<br><br>


title: DESCRIPTION
content:
<i>vboxmanage movevm</i> is a subcommand of the <b>vboxmanage</b> utility, which is the command-line interface for Oracle VirtualBox. This specific command allows you to relocate a virtual machine's entire set of files, including its configuration file (<i>.vbox</i>), its virtual disk images (<i>.vdi</i>, <i>.vmdk</i>, etc.), and other associated data, from its current storage location on the host file system to a new specified directory.<br><br>It's crucial that the virtual machine is powered off before attempting this operation, as moving files while the VM is running can lead to data corruption. The command handles the internal updates required within VirtualBox's registry to reflect the new paths, ensuring that VirtualBox can still find and manage the VM after the move. This command is particularly useful for organizing storage, migrating VMs to faster disks, or consolidating VM files.


title: CAVEATS
content:
<ul><li><b>VM State:</b> The virtual machine must be powered off (<i>Powered Off</i> state) before executing this command. Attempting to move a running or saved VM will result in an error.</li><li><b>Disk Space:</b> Ensure the target location has sufficient free disk space to accommodate all the VM's files.</li><li><b>Permissions:</b> The user executing the command must have appropriate read and write permissions to both the source and target directories.</li><li><b>Snapshots:</b> The command handles moving snapshots associated with the VM, but it's always good practice to back up critical VMs before major operations.</li><li><b>Shared Folders/USB Filters:</b> While the VM files are moved, any host-specific configurations like shared folders or USB device filters might need re-checking if paths or devices change.</li></ul>


title: FILES MOVED
content:
This command moves the VM's configuration file (<i>.vbox</i>), all associated virtual disk images (<i>.vdi</i>, <i>.vmdk</i>, <i>.vhd</i>, etc.), snapshot files, log files, and other related data.


title: INTERNAL UPDATES
content:
Beyond just moving files, <i>vboxmanage movevm</i> also updates VirtualBox's internal registry and the VM's configuration file to reflect the new paths for the virtual disks and other components, ensuring the VM remains functional without manual path adjustments.


title: NO COPY OPTION
content:
There is no built-in <b>--copy</b> option; <i>movevm</i> performs a move operation, which means the files are physically transferred to the new location and deleted from the old. If you need a copy, you would typically clone the VM or manually copy and then register.


title: HISTORY
content:
VirtualBox, initially developed by Innotek GmbH, was later acquired by Sun Microsystems in 2008 and subsequently by Oracle Corporation in 2010. The <b>vboxmanage</b> utility has been a core component of VirtualBox since its early versions, providing comprehensive command-line control over all aspects of VM management. The <i>movevm</i> subcommand was introduced to streamline the process of relocating VM files, automating the complex task of updating internal configuration files and the VirtualBox registry, which would otherwise be a manual and error-prone process. Its existence reflects the need for robust VM lifecycle management tools in virtualized environments.


title: SYNOPSIS
content:
<pre>VBoxManage registervm &lt;path_to_vbox_file&gt;</pre><i>Note: This command is a subcommand of <b>VBoxManage</b>, not a standalone executable named <b>vboxmanage-registervm</b>.</i>


title: PARAMETERS
content:
<b>&lt;path_to_vbox_file&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;The absolute or relative path to the <b>.vbox</b> XML configuration file of the virtual machine you wish to register. This file contains all settings, hardware definitions, and linked storage for the VM. Example: <i>/home/user/VirtualBox VMs/MyVM/MyVM.vbox</i><br><br>


title: DESCRIPTION
content:
The <b>VBoxManage registervm</b> command is a crucial subcommand of the Oracle VM VirtualBox command-line utility, <b>VBoxManage</b>. Its primary function is to add an existing virtual machine definition back into the VirtualBox inventory. This is particularly useful in scenarios where a virtual machine's configuration file (<i>.vbox</i>) has been manually moved, copied, or restored from a backup, and it no longer appears in the VirtualBox Manager GUI or in the output of <b>VBoxManage list vms</b>.<br><br>Instead of creating a new virtual machine, <b>registervm</b> simply informs VirtualBox about the location of an existing VM's <i>.vbox</i> configuration file, allowing VirtualBox to recognize and manage it once again. It does not move or copy any files; it merely updates the VirtualBox internal database. Users typically provide the full path to the <i>.vbox</i> file as an argument. Upon successful registration, the VM becomes visible and manageable via both the VirtualBox Manager GUI and other <b>VBoxManage</b> subcommands.


title: CAVEATS
content:
The requested command <b>vboxmanage-registervm</b> is not a standalone executable. Instead, <b>registervm</b> is a subcommand of the main <b>VBoxManage</b> utility. All operations are performed using <b>VBoxManage registervm ...</b>.<br><br>The specified <i>.vbox</i> configuration file must exist and be valid. If the file is corrupted or missing, the command will fail.<br><br>This command only registers the VM configuration; it does not automatically resolve issues with missing disk images (VDIs, VHDs, etc.) that the <i>.vbox</i> file refers to. You may need to manually locate or re-register those if they have also been moved.<br><br><b>registervm</b> does not create a new virtual machine; it only brings an existing, previously defined VM back into the VirtualBox inventory.


title: DEFAULT VM LOCATION
content:
By default, VirtualBox stores VM configuration files (<i>.vbox</i>) and associated disk images in a directory structure typically located under your user's home directory, for example, <i>~/VirtualBox VMs/&lt;VM_Name&gt;/&lt;VM_Name&gt;.vbox</i>. When registering a VM, ensure you point to the correct <i>.vbox</i> file within its respective VM folder.


title: UUID CONFLICTS
content:
If you attempt to register a <i>.vbox</i> file that has the same UUID as an already registered VM, <b>VBoxManage</b> will report an error. To resolve this, you might need to unregister the existing VM or use <b>VBoxManage internalcommands sethduuid</b> (or similar for VM UUID) to generate a new UUID for the configuration you wish to register, though this is an advanced operation.


title: HISTORY
content:
Oracle VM VirtualBox, commonly known as VirtualBox, began its life as an open-source virtualization product developed by Innotek GmbH. Acquired by Sun Microsystems in 2008, it subsequently became part of Oracle Corporation in 2010. Throughout its development, <b>VBoxManage</b> has served as the powerful command-line interface for controlling and scripting VirtualBox operations, offering an alternative to the graphical user interface. The <b>registervm</b> subcommand has been a fundamental part of <b>VBoxManage</b> for a long time, evolving alongside the core product to facilitate robust management of virtual machine configurations, especially in headless server environments or for automation tasks.


title: PARAMETERS
content:
<b><I>uuid|name</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the virtual machine by its unique identifier (UUID) or its registered name. This is a mandatory argument.<br><br><b><B>--machinereadable</B></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Outputs the VM information in a key-value pair format (e.g., <B>name="myVM"</B>), which is ideal for scripting and automated parsing. Without this option, the output is formatted for human readability.<br><br>


title: DESCRIPTION
content:
The <B>vboxmanage showvminfo</B> command is a crucial utility within the Oracle VM VirtualBox ecosystem, designed to retrieve and display extensive configuration and runtime details about a specific virtual machine. It provides a comprehensive overview, including the VM's current state (e.g., running, powered off, saved), its hardware settings (e.g., RAM, CPU count, network adapters, storage controllers), connected media, snapshot tree, guest additions status, and more. This command is invaluable for administrators and users needing to inspect VM configurations, troubleshoot issues, or programmatically extract information for scripting and automation tasks. By default, it outputs human-readable information, but it can also generate machine-readable output suitable for parsing by scripts.


title: CAVEATS
content:
The output of <B>showvminfo</B> can be very extensive, especially for complex VM configurations or those with many snapshots. <BR>Ensure the VirtualBox environment is properly set up and the <B>VBoxManage</B> command is in your system's PATH. <BR>If the VM name contains spaces, it must be enclosed in double quotes (e.g., <B>"My VM Name"</B>).


title: OUTPUT CONTENT
content:
The output of <B>showvminfo</B> includes a vast array of details, such as: <BR> <I>General information:</I> Name, UUID, OS type, state. <BR> <I>Hardware details:</I> RAM, VRAM, CPU count, chipset, features (VT-x/AMD-V), I/O APIC, HPET. <BR> <I>Storage controllers and attached disks.</I> <BR> <I>Network adapters:</I> Type, MAC address, attachment mode (NAT, Bridged, Host-only). <BR> <I>USB controllers and devices.</I> <BR> <I>Shared folders.</I> <BR> <I>Snapshot tree.</I> <BR> <I>Guest Additions status.</I> <BR> <I>Clipboard mode, drag and drop mode.</I>


title: USAGE EXAMPLES
content:
<b>To show detailed info for a VM named 'UbuntuDev':</b><br><br><b>vboxmanage showvminfo "UbuntuDev"</b><br><br><b>To get machine-readable info for a VM with a specific UUID:</b><br><br><b>vboxmanage showvminfo 01234567-89ab-cdef-0123-456789abcdef --machinereadable</b>


title: HISTORY
content:
The <B>VBoxManage</B> command-line interface, including <B>showvminfo</B>, has been a core component of Oracle VM VirtualBox since its early versions. It provides a robust, cross-platform way to interact with VirtualBox, paralleling the functionality of the graphical user interface. Over time, the command has evolved to include more detailed information and options, reflecting the growing complexity and feature set of VirtualBox itself, but its fundamental purpose of displaying VM details has remained consistent.


title: SEE ALSO
content:
vboxmanage createvm(1), vboxmanage registervm(1), vboxmanage unregistervm(1), vboxmanage startvm(1), vboxmanage controlvm(1), vboxmanage modifyvm(1), vboxmanage list(1)


title: SYNOPSIS
content:
<b>VBoxManage startvm</b> <<i>uuid</i>|<i>name</i>> [<b>--type</b> <<i>gui</i>|<i>sdl</i>|<i>headless</i>>]


title: PARAMETERS
content:
<b><<i>uuid</i>|<i>name</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The unique identifier (UUID) or the registered name of the virtual machine to be started. This is a mandatory argument to specify which VM to operate on.<br><br><b><b>--type</b> <<i>gui</i>|<i>sdl</i>|<i>headless</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the type of session for the virtual machine.<br><i><b>gui</b></i>: (Default) Starts the VM and opens a full graphical user interface window.<br><i><b>sdl</b></i>: Starts the VM and opens a simpler window using the Simple DirectMedia Layer (SDL) library.<br><i><b>headless</b></i>: Starts the VM completely in the background without any graphical window. This mode is ideal for server environments or when the VM is accessed via RDP/SSH.<br><br>


title: DESCRIPTION
content:
<i>VBoxManage startvm</i> is a powerful subcommand of the <i>VBoxManage</i> utility, which serves as the command-line interface for Oracle VM VirtualBox. This command is used to initiate or resume the execution of a registered virtual machine. It's a fundamental tool for automating VM operations, especially in server environments, scripting, or CI/CD pipelines where a graphical user interface is not desired or available.<br><br>When executed, <i>startvm</i> powers on the specified virtual machine and, depending on the chosen type, opens a graphical window (GUI or SDL) or runs it completely in the background (headless mode). It allows administrators and developers to programmatically control VM lifecycle, making it an essential part of managing VirtualBox instances without direct interaction with the VirtualBox GUI application. This command ensures efficient resource utilization and enables seamless integration of virtualized environments into automated workflows.


title: CAVEATS
content:
<ul><li><b>Resource Availability</b>: Ensure your host machine has sufficient RAM, CPU, and disk resources available for the VM to start successfully.</li><li><b>VM State</b>: If a VM was not properly shut down (e.g., powered off abruptly), it might require a 'discard saved state' or 'poweroff' command using <i>VBoxManage controlvm</i> before it can be started cleanly.</li><li><b>Permissions</b>: The user running <i>VBoxManage</i> must have appropriate permissions to access VirtualBox configuration files and directories.</li><li><b>Path</b>: Ensure <i>VBoxManage</i> is in your system's PATH, or provide its full path (e.g., <i>/usr/bin/VBoxManage</i> on Linux).</li><li><b>Conflicting Sessions</b>: A VM cannot be started if another session for the same VM is already active.</li></ul>


title: FINDING VM IDENTIFIERS
content:
Before starting a VM, you might need its exact name or UUID. You can obtain a list of all registered VMs and their identifiers using the command: <i>VBoxManage list vms</i>.


title: HEADLESS MODE FOR SERVERS
content:
The <i>--type headless</i> option is particularly valuable in server environments or CI/CD pipelines where VMs need to run without a GUI. This mode conserves host resources by not rendering a display and allows for remote management via RDP (if configured) or SSH to the guest OS.


title: HISTORY
content:
Oracle VM VirtualBox, initially developed by Innotek GmbH, introduced <i>VBoxManage</i> as its primary command-line interface from its early versions. When Sun Microsystems acquired Innotek in 2008 and subsequently Oracle acquired Sun in 2010, <i>VBoxManage</i> continued to be a core and continuously developed component. The <i>startvm</i> subcommand has been present since the initial releases, reflecting the fundamental need for programmatic control over VM lifecycle. Its functionality has evolved alongside VirtualBox's features, supporting new session types and error handling mechanisms to provide robust automation capabilities.


title: SEE ALSO
content:
VBoxManage(1), VBoxManage list vms(1), VBoxManage controlvm(1), VBoxManage showvminfo(1), VBoxManage registervm(1)


title: PARAMETERS
content:
<b><I>VM name or UUID</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the name or universally unique identifier (UUID) of the virtual machine to be unregistered. This is a mandatory argument.<br><br><b>--delete</b><br>&nbsp;&nbsp;&nbsp;&nbsp;An optional flag that instructs VirtualBox to permanently delete all associated virtual disk images, snapshots, and saved states along with unregistering the VM definition. Use with extreme caution as this action is irreversible.<br><br>


title: DESCRIPTION
content:
The <b><I>VBoxManage unregistervm</I></b> command is used to remove a virtual machine's definition from the VirtualBox inventory. When a VM is unregistered, it no longer appears in the VirtualBox Manager GUI or in the list returned by <b><I>VBoxManage list vms</I></b>. By default, this command only removes the VM's configuration file (<i>.vbox</i> or <i>.vbox-prev</i>) and its entry from the VirtualBox registry. This means the associated virtual disk images (VDI, VMDK, etc.), snapshots, and saved states remain on the file system.<br><br>The optional <b><I>--delete</I></b> flag significantly alters this behavior. When <b><I>--delete</I></b> is specified, <b><I>VBoxManage unregistervm</I></b> will not only remove the VM definition but also permanently delete all linked virtual disk images, snapshots, and saved states from your storage. This is a powerful, destructive operation and should be used with extreme caution. It's crucial to understand the distinction between unregistering a VM (removing its entry) and deleting its associated files (freeing up disk space). The command requires the VM to be powered off before it can be unregistered.


title: CAVEATS
content:
<b>1. Irreversibility:</b> When the <b><I>--delete</I></b> flag is used, all associated disk images, snapshots, and saved states are permanently removed from your system without a confirmation prompt. Ensure you have backed up any critical data before using this option.<br><b>2. VM State:</b> The virtual machine must be powered off before it can be successfully unregistered. Attempting to unregister a running VM will result in an error.<br><b>3. Partial Deletion:</b> Without the <b><I>--delete</I></b> flag, only the VM definition is removed. Other files like log files or additional attachments (e.g., ISOs) might remain on the disk and need manual cleanup.


title: DISK MANAGEMENT IMPLICATIONS
content:
Understanding the behavior of <b><I>unregistervm</I></b> is critical for disk space management. If you only unregister a VM without the <b><I>--delete</I></b> flag, its virtual disks still consume disk space. You would then need to manually locate and delete the <i>.vdi</i> or other disk image files if you intend to free up storage.


title: SAFETY BEST PRACTICES
content:
Before using <b><I>VBoxManage unregistervm --delete</I></b>, always double-check the VM name/UUID to ensure you are targeting the correct virtual machine. It is highly recommended to create backups of important data or critical VMs before performing such a destructive operation.


title: SEE ALSO
content:
VBoxManage(1), VBoxManage list vms(1), VBoxManage registervm(1), VBoxManage showvminfo(1), VBoxManage closevm(1)


title: SYNOPSIS
content:
<b>VBoxService</b> [<b>-f</b>|<b>--foreground</b>] [<b>-h</b>|<b>--help</b>] [<b>-V</b>|<b>--version</b>] [<I>options</I>]


title: PARAMETERS
content:
<b><b>-f</b>, <b>--foreground</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Runs the service in the foreground, useful for debugging and preventing it from detaching as a background daemon.<br><br><b><b>-h</b>, <b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a help message with available command-line options and usage information.<br><br><b><b>-V</b>, <b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Shows the version information of the <I>VBoxService</I> utility.<br><br><b><b>--disable-timesync</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Disables the automatic time synchronization feature between the guest and host systems.<br><br><b><b>--enable-timesync</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Explicitly enables time synchronization. This is often the default behavior.<br><br><b><b>--debug</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables verbose debugging output, which can be useful for troubleshooting issues with the service.<br><br><b><b>--logfile</b> <I>file</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a file path where the service's log output should be written instead of standard output/error.<br><br><b><b>--pidfile</b> <I>file</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a file to write the process ID (PID) of the service to, typically used by init systems for process management.<br><br>


title: DESCRIPTION
content:
The <I>VBoxService</I> command refers to the daemon process that runs within a Linux guest virtual machine when VirtualBox Guest Additions are installed. It is a crucial component that provides enhanced integration and improved performance between the guest operating system and the VirtualBox host. This service enables a variety of features that significantly improve the user experience in a virtualized environment. These functionalities include:<br><br><b>Shared Clipboard:</b> Allows seamless copying and pasting between the guest and host systems.<br><b>Drag and Drop:</b> Facilitates dragging files and folders directly between the guest and host.<br><b>Time Synchronization:</b> Synchronizes the guest's system clock with the host's clock, preventing time drift.<br><b>Shared Folders:</b> Enables access to host file system directories from within the guest VM.<br><b>Automatic Display Resizing:</b> Adjusts the guest's display resolution automatically when the VM window is resized.<br><b>Seamless Mode:</b> Integrates guest applications directly onto the host desktop.<br><b>Host-Guest Communication:</b> Provides a communication channel for various operations and status reporting.<br><br>The service usually starts automatically at boot as part of the system's service management (e.g., via <I>systemd</I>). While it can be invoked manually for debugging or specific purposes, its primary role is to run continuously in the background, ensuring a smooth and integrated virtualization experience.


title: CAVEATS
content:
The <I>VBoxService</I> command is specific to VirtualBox virtual machines and requires the VirtualBox Guest Additions to be installed within the Linux guest operating system. It is not a general-purpose Linux utility. Direct manual invocation of <I>VBoxService</I> is generally not required for normal operation, as it is designed to run automatically as a background daemon managed by the system's init system (like <I>systemd</I>).<br><br>Features provided by <I>VBoxService</I> like shared folders and display resizing rely on specific kernel modules that are also installed by the Guest Additions. If these modules are not loaded or are incompatible, some functionalities may not work correctly.


title: SYSTEM SERVICE INTEGRATION
content:
<I>VBoxService</I> is typically run as a system daemon, often managed by <I>systemd</I> on modern Linux distributions. Its service unit might be named <I>vboxadd.service</I> or <I>vboxservice.service</I>. Users normally interact with this service via <I>systemctl start|stop|restart|status vboxadd</I> rather than directly invoking the <I>VBoxService</I> binary.


title: GUEST ADDITIONS DEPENDENCY
content:
The functionality of <I>VBoxService</I> is entirely dependent on the successful installation and proper functioning of the VirtualBox Guest Additions. This includes specific kernel modules (e.g., <I>vboxsf</I> for shared folders, <I>vboxguest</I> for core guest functions) that the service interacts with to provide its features.


title: HISTORY
content:
The <I>VBoxService</I> utility has been an integral part of VirtualBox since its early development by Sun Microsystems (later acquired by Oracle). Its evolution has mirrored the development of VirtualBox itself, with continuous improvements in integration features, performance, and compatibility across various Linux distributions. It was designed from the outset to bridge the gap between the virtualized guest and the physical host, making the VM experience feel more native and efficient. Over the years, new features like seamless mode, advanced clipboard sharing, and enhanced 3D acceleration support (via related components) have been integrated, with <I>VBoxService</I> acting as the central communication agent.


title: PARAMETERS
content:
<b>help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a comprehensive list of all available <b>vcgencmd</b> commands and their basic usage.<br><br><b>commands</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Lists only the names of all available <b>vcgencmd</b> commands.<br><br><b>version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Outputs the current firmware version and build date of the Raspberry Pi's VideoCore GPU.<br><br><b>measure_temp</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Reports the current temperature of the VideoCore GPU, typically in degrees Celsius.<br><br><b>measure_clock <I>component</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Shows the clock frequency of a specified system component. Common components include <b>arm</b> (CPU), <b>core</b> (GPU core), <b>h264</b> (video encoder), <b>isp</b> (Image Sensor Pipeline), and <b>v3d</b> (3D graphics).<br><br><b>measure_volts <I>component</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays the voltage level of a specified hardware component. Common components include <b>core</b> (GPU core), <b>sdram_c</b> (SDRAM core), <b>sdram_p</b> (SDRAM PHY), and <b>sdram_i</b> (SDRAM I/O).<br><br><b>get_mem <I>component</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Indicates the amount of memory (in MB) allocated to a specific component. Typically used with <b>arm</b> (for CPU) or <b>gpu</b> (for VideoCore).<br><br><b>get_throttled</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Retrieves the current throttling status, indicating if the system is under-voltaged, capped, or has reached thermal limits. The output is a bitmask.<br><br><b>get_config <I>config_item</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Reads a specific configuration parameter from the system's <b>config.txt</b> file, such as <b>arm_freq</b> or <b>gpu_mem</b>.<br><br><b>codec_enabled <I>codec_name</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Checks if a specific video codec is enabled. Examples include <b>H264</b>, <b>MPG2</b>, <b>WVC1</b>, <b>MPG4</b>, etc.<br><br><b>display_power <I>0|1</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Controls the power state of the connected display. Use <b>0</b> to turn off the display and <b>1</b> to turn it on.<br><br><b>get_camera</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Reports the status of the Raspberry Pi camera module, indicating if it is detected and enabled.<br><br><b>otp_dump</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Dumps the contents of the One-Time Programmable (OTP) memory, which stores unique device information and license keys.<br><br><b>get_board_revision</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Returns the revision code of the Raspberry Pi board, which can be used to identify the specific model and its features.<br><br><b>get_pixels</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provides information about the current display resolution and refresh rate.<br><br>


title: DESCRIPTION
content:
The <b>vcgencmd</b> command is a powerful utility designed for Raspberry Pi devices, providing an interface to interact with the Broadcom VideoCore IV GPU. It allows users to retrieve a wide array of system information and control certain low-level hardware features that are managed by the GPU firmware.<br><br>Primarily used for diagnostics, performance monitoring, and advanced system configuration, <b>vcgencmd</b> can report on critical system metrics such as CPU and GPU temperature, clock frequencies of various components (ARM, core, V3D), voltage levels, and memory allocation between the ARM CPU and the GPU. It also provides insights into throttling status, firmware versions, camera module status, display power control, and information about supported video codecs.<br><br>As it directly interacts with the VideoCore firmware, <b>vcgencmd</b> is specific to Raspberry Pi hardware (models using Broadcom BCM283x/271x SoCs) and is an indispensable tool for understanding and fine-tuning the performance of these single-board computers.


title: CAVEATS
content:
<b>vcgencmd</b> is exclusively designed for Raspberry Pi hardware and relies on the specific Broadcom VideoCore GPU firmware. It is not available or functional on other Linux systems.<br><br>While many commands can be run by a regular user, some operations, particularly those that modify settings or access sensitive hardware information, may require root privileges (e.g., using <b>sudo</b>). The output format is typically plain text, often in key=value pairs, which can be parsed by scripts.


title: USAGE AND SCRIPTING
content:
<b>vcgencmd</b> is frequently used in shell scripts for automated monitoring, system status checks, and dynamic configuration adjustments. Its simple text output makes it easy to parse with standard command-line tools like <b>grep</b>, <b>awk</b>, and <b>cut</b>. For example, to log the GPU temperature every minute, one might use a simple cron job that calls <b>vcgencmd measure_temp</b>.


title: UNDERSTANDING THROTTLING
content:
The output of <b>vcgencmd get_throttled</b> is a bitmask. Interpreting this value allows users to diagnose power supply issues (under-voltage), thermal throttling (over-temperature), or frequency capping due to various reasons. Consulting the official Raspberry Pi documentation provides a full breakdown of the bitmask values.


title: HISTORY
content:
The <b>vcgencmd</b> utility emerged as part of the official Raspberry Pi userland tools, developed by Broadcom and the Raspberry Pi Foundation. Its inception was crucial for providing a user-space interface to the closed-source VideoCore IV GPU firmware, which manages significant aspects of the Raspberry Pi's hardware, including multimedia processing and power management.<br><br>Over time, as new Raspberry Pi models were released and the firmware evolved, <b>vcgencmd</b> has been updated to expose new functionalities, report on additional hardware components, and provide more detailed diagnostics. It has consistently been a core component for advanced users and developers for debugging, monitoring, and fine-tuning Raspberry Pi systems, solidifying its role as an essential low-level command-line tool.


title: SYNOPSIS
content:
<b>vcluster</b> <i>[command] [flags]</i><br><b>vcluster</b> <i>create [vcluster-name] [flags]</i><br><b>vcluster</b> <i>connect [vcluster-name] [flags]</i><br><b>vcluster</b> <i>delete [vcluster-name] [flags]</i><br><b>vcluster</b> <i>list [flags]</i>


title: PARAMETERS
content:
<b><i>[vcluster-name]</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The name of the virtual cluster to operate on.<br><br><b><b>-n, --namespace</b> <i>[namespace]</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the host cluster namespace where the vcluster is located or will be created. Defaults to 'vcluster' or current kube-context's namespace.<br><br><b><b>--kube-config</b> <i>[path]</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Path to the kubeconfig file to use for the host cluster or to write vcluster connection details.<br><br><b><b>--context</b> <i>[context-name]</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The Kubernetes context on the host cluster to use.<br><br><b><b>--set</b> <i>[key=value]</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Used with 'create' to set Helm chart values for the vcluster deployment (e.g., `--set controlPlane.distro=k3s`). Can be specified multiple times.<br><br><b><b>-d, --distro</b> <i>[distro]</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the Kubernetes distribution for the virtual cluster (e.g., 'k3s', 'k8s', 'eks', 'microk8s', 'kind'). Used with 'create'.<br><br><b><b>--version</b> <i>[version]</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the version of the vcluster Helm chart to deploy. Used with 'create'.<br><br><b><b>--expose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Exposes the vcluster API server via an ingress or service on the host cluster. Used with 'create'.<br><br><b><b>--connect</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Automatically connects to the virtual cluster after creation, updating the local kubeconfig. Used with 'create'.<br><br><b><b>--update-current</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Updates the current kube-context to connect to the vcluster. Used with 'connect'.<br><br><b><b>--server</b> <i>[port]</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the local port for the proxy server when connecting to a vcluster. Used with 'connect'.<br><br><b><b>--debug</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables debug logging for more verbose output.<br><br><b><b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays help information for the command or subcommand.<br><br>


title: DESCRIPTION
content:
<i>vcluster</i> is a powerful open-source tool that enables the creation of highly efficient, isolated virtual Kubernetes clusters within a single, larger host Kubernetes cluster. Instead of provisioning separate, full-fledged Kubernetes clusters for each team, project, or development environment, <i>vcluster</i> allows multiple virtual clusters to share the underlying resources of a host cluster while maintaining complete isolation at the API level. Each <i>vcluster</i> provides its own API server, controller manager, and data store, appearing to users as a regular, dedicated Kubernetes cluster. This architecture significantly reduces resource consumption, operational overhead, and spin-up times compared to traditional cluster provisioning. It's an ideal solution for multi-tenancy, enabling developers to work in isolated sandboxes, facilitating CI/CD pipelines with ephemeral environments, and significantly lowering infrastructure costs. Workloads within a <i>vcluster</i> are transformed and run as pods and other resources directly within a designated namespace on the host cluster, ensuring efficient resource utilization and simplified management.


title: CAVEATS
content:
While <i>vcluster</i> provides strong isolation at the API level, it's important to remember that all virtual cluster workloads run as pods within the host cluster's namespace. This means that host cluster resources (CPU, memory, network) are shared, and resource quotas are applied at the host namespace level. Advanced network policies, CNI plugins, or storage class configurations on the host might require specific attention or configuration within the <i>vcluster</i> to function as expected. <i>vcluster</i> is not designed for complete hypervisor-level isolation and relies on Kubernetes' native multi-tenancy capabilities and network segmentation.


title: VIRTUAL CLUSTER ARCHITECTURE
content:
A <i>vcluster</i> operates by deploying a dedicated pod in the host cluster that contains its own API server, controller manager, and a lightweight data store (e.g., sqlite or etcd). When users interact with the <i>vcluster</i>'s API, the <i>vcluster</i> controller intercepts these requests and transforms the virtual resources (e.g., a virtual pod) into corresponding host resources (a real pod in the host namespace). This 'synchronization' ensures that workloads defined within the <i>vcluster</i> run as actual pods on the host cluster, while providing the user with the illusion of a fully dedicated cluster.


title: KEY USE CASES
content:
The primary use cases for <i>vcluster</i> include multi-tenancy scenarios where different teams or projects require isolated Kubernetes environments without the overhead of dedicated clusters. It's highly beneficial for CI/CD pipelines to create fast, ephemeral testing environments. Developers can use <i>vcluster</i> to get personal, isolated sandboxes for application development and testing, ensuring their changes don't interfere with others. It also provides a cost-effective way to manage numerous Kubernetes environments for demos, training, or transient workloads.


title: HISTORY
content:
<i>vcluster</i> was developed by Loft Labs, an organization focused on developer tooling for Kubernetes. It was open-sourced to address the growing need for lightweight, isolated development and CI/CD environments in Kubernetes. Prior to <i>vcluster</i>, achieving such isolation often required provisioning expensive and resource-intensive full Kubernetes clusters. <i>vcluster</i> gained rapid adoption due to its efficiency and the ease with which it allows developers to obtain personal, ephemeral clusters without significant overhead. Its development focuses on providing a familiar Kubernetes experience while optimizing resource utilization on a shared host.


title: SEE ALSO
content:
kubectl(1): The primary command-line tool for interacting with Kubernetes clusters., helm(1): A package manager for Kubernetes, used by <i>vcluster</i> for deploying virtual clusters., k3s(8): A lightweight Kubernetes distribution often used as a backend for virtual clusters., kind(1): Kubernetes IN Docker, a tool for running local Kubernetes clusters that shares some conceptual similarities for local development.


title: PARAMETERS
content:
<b>install <i>&lt;package&gt;...</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Installs one or more specified packages and their dependencies for a given triplet (e.g., x64-linux).<br><br><b>search [<i>pattern</i>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Searches for available packages in the vcpkg registry. A pattern can be provided to filter results by name.<br><br><b>list</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Lists all currently installed packages, along with their versions and triplet information.<br><br><b>remove <i>&lt;package&gt;...</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Removes one or more specified installed packages. This also removes any packages that solely depended on the removed ones.<br><br><b>update</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Updates the vcpkg tool itself and checks for available updates to installed packages. It can also update installed ports.<br><br><b>integrate install</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Integrates vcpkg with your development environment, primarily CMake and MSBuild, to simplify finding installed libraries by projects.<br><br><b>build <i>&lt;package&gt;</i> [<i>options</i>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Builds a specific package from source without necessarily installing it into the default location. Useful for debugging build issues.<br><br><b>export <i>&lt;package&gt;...</i> [<i>options</i>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Exports specified installed packages into a distributable format such as a NuGet package, a zip file, or a 7zip archive.<br><br><b>owns <i>&lt;file&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Determines which installed vcpkg package owns a given file path by searching through installed package files.<br><br><b>env [<i>options</i>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Launches a shell with vcpkg's environment variables set, which can be useful for manual compilation or debugging within the vcpkg environment.<br><br><b>help [<i>command</i>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays help information for the vcpkg tool itself or detailed help for a specific subcommand.<br><br>


title: DESCRIPTION
content:
<i>vcpkg</i> is a free and open-source C/C++ package manager developed by Microsoft. Its primary purpose is to simplify the acquisition and management of C and C++ libraries for various development environments, including Visual Studio, Visual Studio Code, and CMake projects. It supports multiple platforms like Windows, Linux, and macOS. <i>vcpkg</i> builds libraries from source, which offers greater flexibility in terms of compiler versions and configurations, but can also lead to longer installation times. It integrates well with CMake via toolchain files, allowing projects to easily find and link against installed libraries. It also handles transitive dependencies automatically, making dependency management easier for complex C++ projects.


title: CAVEATS
content:
<b>Slow Installation:</b> <i>vcpkg</i> builds libraries from source, which can lead to significantly longer installation times compared to binary package managers, especially for large projects or on slower machines.<br><b>Disk Space Usage:</b> Due to source-based builds and the caching of build artifacts, <i>vcpkg</i> can consume a substantial amount of disk space.<br><b>Compiler Dependency:</b> Requires a compatible C/C++ compiler toolchain (e.g., GCC, Clang on Linux) to be pre-installed and properly configured on the system.<br><b>C++ Specific:</b> It is primarily designed for managing C/C++ libraries and is not a general-purpose system package manager like <i>apt</i> or <i>dnf</i>.


title: TRIPLETS
content:
<i>vcpkg</i> uses the concept of <b>triplets</b> to define a specific target platform, architecture, and configuration (e.g., <i>x64-linux</i> for 64-bit Linux, or <i>x86-windows-static</i> for 32-bit Windows with static linking). Packages are installed for specific triplets, allowing multiple configurations of the same library to coexist and be managed independently.


title: MANIFEST FILES (VCPKG.JSON)
content:
For per-project dependency management, <i>vcpkg</i> supports <b>manifest files</b> (<i>vcpkg.json</i>). This file defines the project's direct and transitive dependencies and features, enabling <i>vcpkg</i> to automatically install necessary libraries when configured with CMake or other build systems, promoting reproducible builds.


title: TOOLCHAIN INTEGRATION
content:
<i>vcpkg</i> integrates seamlessly with CMake via a <b>toolchain file</b> (<i>vcpkg.cmake</i>). By passing <code>-DCMAKE_TOOLCHAIN_FILE=&lt;path_to_vcpkg&gt;/scripts/buildsystems/vcpkg.cmake</code> to CMake, projects can automatically find and link against libraries installed by <i>vcpkg</i>, simplifying the build process significantly.


title: HISTORY
content:
<i>vcpkg</i> was initially developed by Microsoft in 2016 to address the inherent challenges of managing C++ libraries on Windows, particularly within the Visual Studio ecosystem. Its early focus was on providing a consistent and reliable way to acquire and link third-party dependencies. Over time, its scope expanded significantly to become a robust cross-platform solution, supporting Linux and macOS, and integrating seamlessly with CMake-based build systems. Its design philosophy emphasizes building libraries from source, which offers maximum flexibility and control over compiler versions and configurations, contributing to its growing adoption within the C++ development community for complex dependency management.


title: PARAMETERS
content:
<b><i>OPTIONS</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Global options that can be applied before any <i>vcsh</i> command to modify its behavior.<br><br><b>-d, --dry-run</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Perform a dry run; show what would be done without actually making changes to files or repositories.<br><br><b>-v, --verbose</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Increase the verbosity of <i>vcsh</i>'s output, providing more detailed information about its operations.<br><br><b>--config &lt;file&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify an alternative configuration file to use instead of the default <code>~/.config/vcsh/config</code>.<br><br><b>--repo &lt;repo_name&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the dotfile repository (or repositories, if used multiple times) on which the subsequent command should operate. If omitted for some commands, it may operate on all repositories or require selection.<br><br><b>--list-repo</b><br>&nbsp;&nbsp;&nbsp;&nbsp;List all <i>vcsh</i> repositories currently known and managed by <i>vcsh</i> on the system.<br><br><b><i>COMMAND</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The specific operation to perform. <i>vcsh</i> dispatches to various subcommands, many of which mirror standard Git commands.<br><br><b>add &lt;file&gt;...</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Add file contents from your home directory to the index of the selected <i>vcsh</i> repository, preparing them for commit.<br><br><b>clone &lt;url&gt; &lt;repo_name&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Clone an existing Git repository from a URL into <i>vcsh</i>, assigning it a local <i>repo_name</i> for management.<br><br><b>commit [<i>OPTIONS</i>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Record changes to the repository by creating a new commit containing the currently staged contents.<br><br><b>exec &lt;repo_name&gt; -- &lt;git_command&gt; [<i>ARGUMENTS</i>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Execute an arbitrary Git command directly within the specified <i>vcsh</i> repository. The <code>--</code> acts as a separator between <i>vcsh</i> arguments and Git command arguments.<br><br><b>init &lt;repo_name&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Initialize a new, empty <i>vcsh</i> repository with the given name, ready for adding dotfiles.<br><br><b>link [<i>repo_name</i>...]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Ensures that files from the specified (or all) <i>vcsh</i> repositories are correctly placed or linked into your home directory. Useful after cloning or pulling changes.<br><br><b>list</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a list of all configured <i>vcsh</i> repositories, similar to <code>--list-repo</code>.<br><br><b>pull [<i>OPTIONS</i>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Fetch changes from the remote repository and integrate them into the local <i>vcsh</i> repository.<br><br><b>push [<i>OPTIONS</i>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Update remote references along with associated objects from the local <i>vcsh</i> repository.<br><br><b>status</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Show the working tree status for the selected (or all) <i>vcsh</i> repositories, indicating modified, added, or untracked files.<br><br><b>update [<i>repo_name</i>...]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Update one or all <i>vcsh</i> repositories by pulling changes from their remotes and linking them into the home directory.<br><br>


title: DESCRIPTION
content:
<i>vcsh</i> (<b>v</b>ersion <b>c</b>ontrol <b>sh</b>ell) is a powerful command-line tool designed to manage your dotfiles (configuration files) using Git, but with a unique approach that fosters isolation and flexibility. Instead of maintaining a single, monolithic Git repository for all your dotfiles, <i>vcsh</i> allows you to create separate, independent Git repositories for different sets of configurations—for example, one for your Vim settings, another for Bash, and yet another for Git configurations.<br><br>It operates by creating bare Git repositories for each dotfile collection in a dedicated hidden directory (typically <code>~/.config/vcsh/repo.d/</code>). These repositories then transparently project their contents into your home directory, making them appear as if they reside there directly. This method avoids the complexities of symlink farms, Git submodules, or large, unmanageable repositories.<br><br><i>vcsh</i> acts as a user-friendly wrapper around standard Git commands. It enables you to perform common Git operations like <code>add</code>, <code>commit</code>, <code>push</code>, and <code>pull</code> on specific dotfile repositories, simplifying the management of configurations across different machines, sharing specific subsets of dotfiles, and preventing accidental exposure of sensitive information.


title: CAVEATS
content:
Effective use of <i>vcsh</i> benefits from a solid understanding of Git, especially the concept of bare repositories. Initial setup and advanced configurations can sometimes be complex, requiring manual intervention for conflicts or specific linking needs. As <i>vcsh</i> directly interacts with files in your home directory, careful management is advised to prevent conflicts if other dotfile management tools are also in use. It does not provide built-in secrets management; users should employ separate tools like <i>git-crypt</i> or <i>age</i> for sensitive information.


title: HOW IT WORKS
content:
<i>vcsh</i>'s core mechanism involves creating bare Git repositories for each dotfile group (e.g., 'bash', 'vim') within a hidden directory, commonly <code>~/.config/vcsh/repo.d/</code>. When you run a <i>vcsh</i> command like <code>vcsh commit bash</code>, <i>vcsh</i> effectively executes the corresponding Git command from within the <code>~/.config/vcsh/repo.d/bash.git</code> repository, using your home directory (<code>~</code>) as the working tree. The <code>vcsh link</code> command (or implicit linking during <code>vcsh update</code>) ensures that the files tracked by these bare repositories are correctly placed or synchronized in your home directory, providing a seamless user experience without requiring traditional working directories for each Git repo.


title: CONFIGURATION AND HOOKS
content:
<i>vcsh</i> can be extensively configured via a main configuration file, usually located at <code>~/.config/vcsh/config</code>. This file allows users to define custom aliases, global settings, and even repository-specific configurations. A powerful feature is the ability to define hooks (e.g., <code>post-checkout</code>, <code>post-merge</code>) that automatically execute scripts or commands after certain Git operations within a <i>vcsh</i> repository. This enables automation of tasks like compiling configuration files, running linters, or restarting services when dotfiles are updated.


title: HISTORY
content:
<i>vcsh</i> was created by Richi Plana in 2011 to address the limitations of existing dotfile management approaches. Its primary goal was to provide a flexible and robust system that avoids monolithic Git repositories, complex symlink farms, and the accidental exposure of sensitive data. By leveraging Git's bare repository functionality, <i>vcsh</i> offered a novel solution for managing distinct sets of configuration files while making them appear to reside cohesively within the user's home directory.


title: PARAMETERS
content:
<b><b>-h</b>, <b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a help message and exits.<br><br><b><b>-v</b>, <b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Shows version information and exits.<br><br><b><b>-r</b> <i>&lt;path&gt;</i>, <b>--repo</b> <i>&lt;path&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the path to the VCS repository to analyze. Defaults to the current directory.<br><br><b><b>-s</b> <i>&lt;date&gt;</i>, <b>--since</b> <i>&lt;date&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Filters activity to show commits or changes since a specified date or time (e.g., '2 weeks ago', '2023-01-01').<br><br><b><b>-u</b> <i>&lt;date&gt;</i>, <b>--until</b> <i>&lt;date&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Filters activity to show commits or changes until a specified date or time.<br><br><b><b>-a</b> <i>&lt;name&gt;</i>, <b>--author</b> <i>&lt;name&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Filters activity by the specified author name or email.<br><br><b><b>-b</b> <i>&lt;branch&gt;</i>, <b>--branch</b> <i>&lt;branch&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Focuses analysis on a specific branch of the repository.<br><br><b><b>-f</b> <i>&lt;format&gt;</i>, <b>--format</b> <i>&lt;format&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the output format (e.g., '<i>json</i>', '<i>csv</i>', '<i>human-readable</i>').<br><br><b><b>-c</b> <i>&lt;count&gt;</i>, <b>--count</b> <i>&lt;count&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Limits the number of results or commits to process.<br><br>


title: DESCRIPTION
content:
The `<b>vcstime</b>` command, <i>as a conceptual utility</i>, would provide tools for analyzing and reporting time-related data within version control systems (VCS). This could include displaying commit timestamps, tracking time spent on branches or specific commits, or generating detailed reports based on activity logs. Its primary aim would be to offer insights into development velocity, resource allocation, and project progression by leveraging the rich historical data available in VCS repositories. Users could hypothetically query by author, date range, or repository path to gain granular understanding of project timelines and individual contributions.


title: CAVEATS
content:
It is important to note that `<b>vcstime</b>` is <i>not a standard, widely distributed Linux command</i>. This analysis is based on a conceptual interpretation of its name ('Version Control System Time') and outlines what such a command <i>might</i> do if it existed as a dedicated utility. Users attempting to execute `<b>vcstime</b>` on most Linux systems will likely encounter a '<i>command not found</i>' error. It could potentially exist as a custom script, an internal function within a specific third-party VCS client or time-tracking application, or be a typo for another command.


title: <B>CONCEPTUAL USE CASES</B>
content:
<ul><li><i><b>Project Management:</b></i> Hypothetically, `<b>vcstime</b>` could assist project managers in assessing developer activity, estimating effort, and monitoring project progress by providing metrics derived from VCS commit history and timestamps.</li><li><i><b>Developer Insights:</b></i> Developers might use `<b>vcstime</b>` to review their own work patterns, identify periods of high activity or bottlenecks, or understand the time distribution across different features, branches, or bug fixes.</li><li><i><b>Auditing and Reporting:</b></i> It could serve as a tool for auditing development cycles, generating compliance reports based on commit timestamps, or providing data for billing in time-sensitive projects.</li></ul>


title: HISTORY
content:
As `<b>vcstime</b>` is not a standard, universally recognized Linux command, there is no widely documented development or usage history associated with it. If a tool with this name were to emerge, its evolution would likely be driven by the increasing demand for advanced analytics, reporting, and time management within modern software development workflows, particularly those heavily reliant on version control systems.


title: PARAMETERS
content:
<b>All <b>ls</b> options</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Since <b>vdir</b> is fundamentally an alias for <b>ls -l</b>, it accepts and processes all options that the <b>ls</b> command supports. The <b>-l</b> option is implicitly applied, meaning any additional <b>ls</b> options will modify the detailed output further. For example, options like <b>-a</b> (to show hidden files), <b>-h</b> (for human-readable sizes), or <b>-t</b> (to sort by modification time) can be combined with <b>vdir</b>.<br><br><b>-a, --all</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Do not ignore entries starting with '.'. This reveals hidden files and directories that typically start with a dot.<br><br><b>-h, --human-readable</b><br>&nbsp;&nbsp;&nbsp;&nbsp;With <b>-l</b>, print human readable sizes (e.g., 1K, 234M, 2G) instead of raw bytes, making output easier to read.<br><br><b>-r, --reverse</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Reverse order while sorting. This can be used to reverse the default alphabetic sort or a time/size sort.<br><br><b>-t</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sort by modification time, newest first. If two files have the same modification time, their order is then determined by their name.<br><br><b>-S</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sort by file size, largest first. If two files have the same size, their order is then determined by their name.<br><br><b>-R, --recursive</b><br>&nbsp;&nbsp;&nbsp;&nbsp;List subdirectories recursively. This displays the contents of directories and their subdirectories, providing a comprehensive view.<br><br>


title: DESCRIPTION
content:
<i>vdir</i> is a command that acts as a convenience wrapper or symbolic link, typically to <b>ls -l</b>. Its primary function is to display the contents of directories in a detailed, long listing format. This format includes essential file information such as file permissions, the number of hard links, the owner's username, the group's name, the file size (in bytes by default), the last modification date and time, and the filename or directory name. <br><br>Essentially, <i>vdir</i> provides a quick way to get a verbose listing of files and directories, equivalent to typing 'ls -l' in the terminal. It is part of the GNU coreutils package and is widely available on most Unix-like operating systems, streamlining common file system inspection tasks by reducing keystrokes for a frequently desired output format.


title: CAVEATS
content:
The behavior of <b>vdir</b> is entirely dependent on the underlying <b>ls</b> command on the system. It does not introduce any new or unique functionality beyond what <b>ls -l</b> provides. If <b>ls</b> is configured with aliases or specific environment variables (e.g., LS_COLORS), <b>vdir</b> will inherit those as well, which might slightly alter its output appearance (e.g., colorized output).


title: IMPLEMENTATION
content:
On most Linux distributions, <b>vdir</b> is implemented as a hard link or symbolic link to the <b>ls</b> executable. When <b>vdir</b> is executed, it effectively calls <b>ls</b> internally with the <b>-l</b> option pre-applied. This lightweight implementation means it consumes minimal additional system resources compared to directly calling <b>ls -l</b>, serving purely as a syntactic convenience.


title: HISTORY
content:
<b>vdir</b> is part of the GNU coreutils, a fundamental package of utilities for Unix-like operating systems. Its inclusion reflects a common usage pattern where users frequently require detailed listings of directory contents. Rather than repeatedly typing 'ls -l', <b>vdir</b> (along with <b>dir</b> for 'ls -C') was provided as a convenient shorthand. This practice of offering specific aliases for common command option combinations enhances usability and efficiency for command-line users, making frequently used commands more accessible.


title: SYNOPSIS
content:
<b>vegeta</b> <i>&lt;command&gt;</i> [<i>options</i>] [<i>arguments</i>]<br><br>Common usage for load testing:<br><b>vegeta attack</b> <i>-targets=&lt;file|url&gt;</i> <i>-rate=&lt;rate&gt;</i> <i>-duration=&lt;duration&gt;</i> [<i>options</i>]<br><b>vegeta report</b> [<i>options</i>]


title: PARAMETERS
content:
<b><b>-targets</b> <i>string</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the source of attack targets. This can be a file path containing one target per line, or a single URL directly. Targets can be simple URLs or more complex HTTP requests with headers and bodies.<br><br><b><b>-rate</b> <i>string</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The request rate to send, expressed as 'requests/duration' (e.g., '500/1s' for 500 requests per second, or '100/1m' for 100 requests per minute). This defines the sustained attack rate.<br><br><b><b>-duration</b> <i>duration</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The total duration of the attack (e.g., '10s', '5m', '1h'). The attack will stop after this duration, regardless of the number of requests sent.<br><br><b><b>-output</b> <i>string</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;File path to write the binary attack results to. If not specified, results are written to standard output (STDOUT), which is typically piped to another command like <b>vegeta report</b>.<br><br><b><b>-connections</b> <i>uint</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Maximum number of concurrent connections the attacker can open. Defaults to 10000.<br><br><b><b>-timeout</b> <i>duration</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Maximum time a single request is allowed to take. If a response is not received within this duration, the request is considered a timeout error. Defaults to 0 (no timeout).<br><br><b><b>-header</b> <i>string</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Adds a custom HTTP header to all requests in the format 'Key: Value'. Can be specified multiple times for multiple headers.<br><br><b><b>-body</b> <i>string</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the request body for POST/PUT requests. Can be a file path (prefixed with '@') or a string literal.<br><br><b><b>-insecure</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;When set, disables TLS certificate validation. Useful for testing services with self-signed certificates or during development.<br><br><b><b>-workers</b> <i>uint</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The number of concurrent attack workers. More workers can generate higher loads, but also consume more local resources. Defaults to 10.<br><br>


title: DESCRIPTION
content:
<i>vegeta</i> is a versatile and high-performance HTTP load testing and API benchmarking tool. Written in Go, it excels at generating sustained request rates against web services and APIs, making it ideal for performance analysis, stress testing, and identifying bottlenecks. Users can define various attack parameters such as target URLs, request rate, and duration. <i>vegeta</i> provides a comprehensive set of output metrics including latency percentiles, request success rates, and throughput. Its binary output format can be piped to other <i>vegeta</i> sub-commands like <i>report</i> for human-readable summaries, <i>dump</i> for detailed request/response logs, or <i>plot</i> for generating graphical representations. It's renowned for its efficiency and ease of use, enabling developers and operations teams to quickly assess the resilience and performance characteristics of their applications under various loads. It's often chosen for its ability to simulate realistic traffic patterns with minimal resource overhead on the testing machine itself.


title: CAVEATS
content:
<b>vegeta</b> is not a standard Linux distribution command; it needs to be installed separately, typically via Go or by downloading a pre-compiled binary.<br>For very high request rates, ensure the attacking machine has sufficient network bandwidth, CPU, and memory, as <b>vegeta</b> can be resource-intensive.<br>The raw output of the <b>attack</b> command is in a binary format, which requires piping to <b>vegeta report</b>, <b>vegeta dump</b>, or <b>vegeta plot</b> for human-readable or visual analysis. Neglecting this step can lead to confusion about results.


title: USAGE PATTERNS
content:
The most common way to use <b>vegeta</b> is by chaining its sub-commands, typically <b>attack</b> and <b>report</b>, using a pipe. For instance, `vegeta attack -targets=targets.txt -rate=100/1s | vegeta report` performs an attack and immediately displays a summary report. Alternatively, results can be saved to a file (`vegeta attack > results.bin`) and analyzed later using `vegeta report < results.bin` or `vegeta dump < results.bin`.


title: TARGET DEFINITION
content:
Targets for <b>vegeta</b> can be simple URLs or more complex definitions in a file, allowing specification of HTTP method, headers, and request body. For example, a <i>targets.txt</i> file can contain:<br><i>GET http://localhost:8080/path<br>POST http://localhost:8080/data<br>@payload.json<br>X-Custom-Header: value</i>


title: HISTORY
content:
<b>vegeta</b> was created by <i>Tarek Ziade</i>, a well-known figure in the open-source community, and is written in the <i>Go</i> programming language. It emerged as a high-performance alternative to existing load testing tools, leveraging Go's concurrency model to efficiently generate and manage a large number of concurrent HTTP requests. Since its initial release, it has gained significant traction among developers and SREs for its simplicity, speed, and comprehensive metrics, becoming a go-to tool for benchmarking and stress-testing HTTP services. The project is actively maintained on GitHub, benefiting from community contributions.


title: SYNOPSIS
content:
<b>vela</b> <i>[command] [flags]</i> <br><br>Common Commands:<br><b>vela up</b> <i>[application_name] [flags]</i> - Deploys or updates an application.<br><b>vela status</b> <i>[application_name] [flags]</i> - Shows the status of an application.<br><b>vela ls</b> <i>[flags]</i> - Lists all applications.<br><b>vela def</b> <i>[command] [flags]</i> - Manages OAM definitions (components, traits, workflows, policies).<br><b>vela show</b> <i>[definition_name] [flags]</i> - Displays details of a definition.


title: PARAMETERS
content:
<b>--help, -h</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Help for any command.<br><br><b>--version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Print the client and server version information.<br><br><b>--kubeconfig <path></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Path to the kubeconfig file to use for CLI requests. Defaults to ~/.kube/config.<br><br><b>--context <name></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The name of the kubeconfig context to use.<br><br><b>--namespace, -n <name></b><br>&nbsp;&nbsp;&nbsp;&nbsp;If present, the namespace scope for this CLI request. Defaults to the current context's namespace.<br><br>


title: DESCRIPTION
content:
<b>vela</b> is the command-line interface (CLI) for <i>KubeVela</i>, an application delivery platform built on top of Kubernetes. It enables developers and operators to deploy, manage, and operate applications across diverse environments, including multi-cluster, hybrid cloud, and edge scenarios, in a unified and declarative manner. <br><br>KubeVela implements the <i>Open Application Model (OAM)</i>, providing a clear separation of concerns between developers (defining application components) and operators (defining operational capabilities like scaling, traffic routing, or health checks). The <b>vela</b> CLI acts as the primary tool for interacting with the KubeVela control plane, allowing users to define applications, manage components and traits, inspect application status, and interact with the underlying Kubernetes resources. It abstracts away much of the complexity of raw Kubernetes YAML, offering a more application-centric approach to deployment and operations.


title: CAVEATS
content:
<b>vela</b> is not a standard Linux command pre-installed on most operating systems. It is a specialized client-side tool for interacting with a <i>KubeVela</i> control plane, which itself must be installed and running on a Kubernetes cluster. <br><br>Its functionality is entirely dependent on the KubeVela installation and the Kubernetes cluster it connects to. Users must have appropriate Kubernetes cluster access configurations (e.g., via `kubeconfig`) for <b>vela</b> to function. Due to the rapid development of KubeVela and OAM, command syntax and available features may evolve between versions.


title: OPEN APPLICATION MODEL (OAM)
content:
KubeVela, and by extension the <b>vela</b> CLI, is built around the <i>Open Application Model (OAM)</i>. OAM provides a standardized, declarative way to define applications that separates concerns between developers (who define application components) and operators (who define how those components are operated, using traits, policies, and workflows). This separation promotes reusability, consistency, and portability across different environments.


title: EXTENSIBILITY
content:
KubeVela is designed to be highly extensible. Users can define custom components, traits, workflows, and policies using CUE or Helm, which are then exposed and managed via the <b>vela</b> CLI. This allows platform builders to extend KubeVela's capabilities to suit specific organizational needs or integrate with proprietary systems, fostering a highly customizable application delivery experience.


title: HISTORY
content:
The <b>vela</b> CLI is an integral part of the <i>KubeVela</i> project, which originated from the <i>Open Application Model (OAM)</i> specification. OAM was co-created by Alibaba Cloud and Microsoft and was later contributed to the <i>Cloud Native Computing Foundation (CNCF)</i>. KubeVela became a CNCF sandbox project in 2020 and later moved to incubating status. The <b>vela</b> CLI was developed as the primary client-side tool to empower developers and operators to adopt the OAM principles for declarative, platform-agnostic application delivery on Kubernetes and beyond. Its development tracks the evolution of the KubeVela platform itself, constantly adding support for new features, components, and operational capabilities introduced by the community.


title: SYNOPSIS
content:
<b>velero</b> <i>&lt;command&gt;</i> [<i>&lt;subcommand&gt;</i>] [<i>&lt;flags&gt;</i>]<br><br><b>Common examples:</b><br><b>velero</b> install --provider aws --bucket my-velero-bucket<br><b>velero</b> backup create <i>&lt;backup-name&gt;</i> --include-namespaces <i>&lt;namespace&gt;</i><br><b>velero</b> restore get


title: PARAMETERS
content:
<b><b>--kubeconfig</b> <i>&lt;path&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Path to the kubeconfig file to use for Kubernetes client configuration. Overrides the default kubeconfig lookup behavior.<br><br><b><b>--context</b> <i>&lt;name&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The name of the kubeconfig context to use. If not specified, the current context from kubeconfig is used.<br><br><b><b>--namespace</b> <i>&lt;name&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The Kubernetes namespace in which the <i>Velero</i> server is running and where <i>Velero</i> resources are stored. Defaults to 'velero'.<br><br><b><b>--log-level</b> <i>&lt;level&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Logging level for the <i>Velero</i> CLI output (e.g., 'debug', 'info', 'warn', 'error'). Defaults to 'info'.<br><br><b><b>--output</b> <i>&lt;format&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Output format for commands that display resources (e.g., 'table', 'json', 'yaml'). Defaults to 'table'.<br><br><b><b>Subcommand-specific Flags</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Most <i>Velero</i> operations are performed via specific subcommands (e.g., <b>backup</b>, <b>restore</b>, <b>install</b>, <b>schedule</b>). Each subcommand has its own unique set of flags and options relevant to its operation, which can be viewed using the <b>--help</b> flag (e.g., <b>velero backup create --help</b>).<br><br>


title: DESCRIPTION
content:
<i>Velero</i> is an open-source tool designed to safely back up, restore, and migrate Kubernetes cluster resources and persistent volumes. It provides a robust solution for disaster recovery and cluster migration, ensuring business continuity for containerized applications.<br><i>Velero</i> operates by taking snapshots of persistent volumes and backing up Kubernetes API objects, allowing for point-in-time recovery of your cluster's state. It captures the state of your cluster's resources, including deployments, services, configurations, and persistent data, making it invaluable for recovering from accidental deletions, cluster failures, or for migrating applications between clusters.<br>It requires a server-side component (the <i>Velero</i> server) running within the Kubernetes cluster and a command-line interface (CLI) for user interaction, enabling operations like creating backups, restoring data, and managing schedules for automated backups.


title: CAVEATS
content:
<i>Velero</i> is not a standard Linux utility but rather a command-line client for a Kubernetes application. Its full functionality requires a <i>Velero</i> server component to be installed and running within a Kubernetes cluster. Furthermore, its ability to back up and restore persistent volumes is highly dependent on the configuration of appropriate object storage (for backup data) and volume snapshot providers (for persistent volume snapshots) within the specific cloud or on-premise environment.


title: ARCHITECTURE
content:
<i>Velero</i> operates on a client-server model. The <i>Velero</i> CLI, used on a user's local machine or CI/CD pipeline, interacts with the <i>Velero</i> server components running as deployments and custom resources within a Kubernetes cluster. The server coordinates backup and restore operations by interacting with the Kubernetes API, object storage providers, and volume snapshot providers to manage cluster state and data.


title: STORAGE BACKENDS AND PLUGINS
content:
<i>Velero</i> supports a wide range of object storage providers (e.g., AWS S3, Google Cloud Storage, Azure Blob Storage, MinIO) for storing backup data. For persistent volume backups, it leverages cloud provider-specific volume snapshot APIs (e.g., AWS EBS snapshots, CSI snapshots). This extensibility is managed through a robust plugin system, allowing users to integrate with various storage solutions and custom resources.


title: HISTORY
content:
Originally developed by Heptio under the name <i>Ark</i>, the project was designed to address the critical need for backup and disaster recovery solutions in dynamic Kubernetes environments.<br>After Heptio was acquired by VMware, the project was rebranded as <i>Velero</i> (Latin for 'sailor' or 'ferryman'), signifying its role in safely transporting and managing Kubernetes data.<br>Since its rebranding, <i>Velero</i> has continued to evolve as a vital open-source project within the Cloud Native Computing Foundation (CNCF) landscape, gaining widespread adoption as a robust standard for Kubernetes backup and restore.


title: PARAMETERS
content:
<b>-h, --help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Show help message and exit.<br><br><b>--system-site-packages</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Give the virtual environment access to the system site-packages directory. By default, environments are isolated.<br><br><b>--symlinks</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Try to symlink rather than copy files. This is often the default on macOS and Windows (Python 3.9+).<br><br><b>--copies</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Try to copy rather than symlink files. Use this if symlinking causes issues.<br><br><b>--clear</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Delete the contents of the environment directory if it already exists, then recreate the environment.<br><br><b>--upgrade-deps</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Upgrade pip, setuptools, and wheel to the latest versions in the created virtual environment (Python 3.9+).<br><br><b>--without-pip</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Skips installing pip, setuptools, and wheel into the new virtual environment.<br><br>


title: DESCRIPTION
content:
The <i>venv</i> module, bundled with Python 3.3 and later, provides a lightweight way to create isolated Python environments. It's not a standalone Linux executable but a module invoked via the Python interpreter: <b>python3 -m venv <directory></b>. <br><br>These virtual environments allow developers to manage project-specific dependencies without interfering with the system-wide Python installation or other projects. Each environment has its own Python interpreter, pip, and an independent set of installed packages. This isolation is crucial for reproducibility and preventing dependency conflicts. Once created, an environment is <i>activated</i>, which modifies the shell's PATH to prioritize the environment's executables, making it seamless to work within the isolated context. Deactivation returns the shell to its previous state. <i>venv</i> is the modern, official approach for virtual environments in Python.


title: CAVEATS
content:
The <i>venv</i> module requires Python 3.3 or later. For Python 2 projects, the external <i>virtualenv</i> tool is typically used. Remember to explicitly <i>activate</i> the environment after creation to use it, and to install packages within it using <i>pip</i>.


title: INVOCATION METHOD
content:
<i>venv</i> is not a standalone executable command. It is invoked as a Python module using the Python interpreter: <b>python3 -m venv <directory_name></b>. This distinction is important as it means you must have a Python 3 interpreter installed to use it.


title: ENVIRONMENT ACTIVATION
content:
After creating a virtual environment, it must be <i>activated</i> to modify your shell's environment variables (like PATH) to point to the environment's Python interpreter and scripts. The activation command varies by shell and operating system:<br><b>Bash/Zsh</b>: <i>source <env_name>/bin/activate</i><br><b>Windows Command Prompt</b>: <i><env_name>\Scripts\activate.bat</i><br><b>PowerShell</b>: <i><env_name>\Scripts\Activate.ps1</i><br>To exit an activated environment, simply run <b>deactivate</b>.


title: HISTORY
content:
The <i>venv</i> module was introduced as a built-in feature in Python 3.3 (released 2012) to provide a standardized, official way to manage virtual environments. Prior to its inclusion, the third-party <i>virtualenv</i> tool was the de-facto standard. <i>venv</i> aims to simplify environment management by integrating it directly into the Python standard library, making it more accessible and reducing external dependencies for basic use cases.


title: SYNOPSIS
content:
<b>veracrypt</b> [<i>options</i>] [<i>volume</i> [<i>mount_directory</i>]]<br><b>veracrypt</b> --create [<i>options</i>]<br><b>veracrypt</b> --dismount [<i>options</i>]<br><b>veracrypt</b> --list [<i>options</i>]


title: PARAMETERS
content:
<b>--create</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Initiates the process to create a new VeraCrypt volume (file container or partition/device).<br><br><b>--dismount [MOUNT_DIRECTORY|ALL]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Dismounts a specific VeraCrypt volume mounted at <i>MOUNT_DIRECTORY</i> or all currently mounted volumes if 'ALL' is specified.<br><br><b>--list</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Lists all currently mounted VeraCrypt volumes, showing their paths and mount points.<br><br><b>--mount [VOLUME] [MOUNT_DIRECTORY]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Mounts a specified VeraCrypt <i>VOLUME</i> (file or device) to the designated <i>MOUNT_DIRECTORY</i>.<br><br><b>-t, --text</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Uses a text-based user interface for operations, useful for scripting or headless environments.<br><br><b>-k, --keyfiles=FILE[,FILE...]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies one or more keyfiles to use for authentication, in addition to or instead of a password.<br><br><b>-p, --password=PASSWORD</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provides the password for the volume directly on the command line. Use with caution as it can be visible in process lists.<br><br><b>--protect-hidden=yes</b><br>&nbsp;&nbsp;&nbsp;&nbsp;When mounting an outer volume, this option ensures that the hidden volume within it remains protected and unmounted.<br><br><b>--force</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces an operation, overriding warnings or confirmation prompts.<br><br><b>--non-interactive</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppresses all user prompts and relies solely on command-line arguments and configuration files for input.<br><br><b>--filesystem=TYPE</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the filesystem type (e.g., ext4, vfat, ntfs) to be created inside the new VeraCrypt volume.<br><br><b>--encryption=ALGO</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the encryption algorithm (e.g., AES, Serpent, Twofish, or cascades like AES-Twofish) for the volume.<br><br><b>--hash=ALGO</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the hash algorithm (e.g., SHA-512, Whirlpool, RIPEMD-160) for key derivation.<br><br><b>--volume-type=TYPE</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies whether to create a 'normal' volume or a 'hidden' volume for plausible deniability.<br><br>


title: DESCRIPTION
content:
VeraCrypt is a powerful, cross-platform, open-source disk encryption software that enhances security over its predecessor, TrueCrypt. It allows users to encrypt an entire storage device (hard drive, SSD, USB drive), a partition on such a device, or create a virtual encrypted disk within a file. VeraCrypt uses strong encryption algorithms like AES, Serpent, and Twofish, often combined in cascade modes, and supports plausible deniability through hidden volumes. It's widely used for protecting sensitive data against unauthorized access, even if the storage medium is lost or stolen. The Linux command-line interface provides comprehensive control for creating, mounting, and managing encrypted volumes.


title: CAVEATS
content:
Using VeraCrypt securely requires careful handling of passwords and keyfiles. Losing these credentials will result in permanent data loss. Performance overhead is expected due to real-time encryption/decryption. Ensure proper dismounting of volumes to prevent data corruption. Hidden volumes provide plausible deniability but require strict adherence to usage protocols to remain effective.


title: SECURITY BEST PRACTICES
content:
Always use strong, unique passwords or robust keyfiles. Avoid storing passwords unencrypted. Regularly back up your encrypted data, as the loss of your password or keyfiles means permanent data loss. For advanced users, consider utilizing hidden volumes for plausible deniability, understanding their specific operational requirements.


title: COMMON USE CASES
content:
VeraCrypt is commonly used for encrypting sensitive documents on laptops, securing backups on external drives, protecting an entire system partition for enhanced operating system security, or creating a secure file container for collaborative work on sensitive data.


title: HISTORY
content:
VeraCrypt originated as a fork of TrueCrypt 7.1a in 2013, following security concerns and the abrupt discontinuation of TrueCrypt. Its primary goal was to address identified vulnerabilities and further enhance the security and robustness of the encryption scheme. It notably increased the number of PBE (Password-Based Key Derivation Function) iterations, making brute-force attacks significantly more difficult. Development continues actively, maintaining compatibility with TrueCrypt volumes while improving security features.


title: SYNOPSIS
content:
<b>vercel</b> [<I>options</I>] [<I>path</I>]<br><b>vercel</b> [<I>options</I>] <I>command</I> [<I>args</I>]<br><br><i>Examples:</i><br><b>vercel</b><br><b>vercel</b> <I>dev</I><br><b>vercel</b> <I>deploy</I> <I>./my-app</I> <I>--prod</I><br><b>vercel</b> <I>login</I><br><b>vercel</b> <I>env</I> <I>add</I> <I>production</I> <I>MY_VAR</I> <I>"my value"</I><br><b>vercel</b> <I>--help</I>


title: PARAMETERS
content:
<b>--prod</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Deploy to the production environment, creating a production-ready URL for your project.<br><br><b>--scope &lt;teamId | teamSlug&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the scope to a specific Team ID or Slug for the command execution, overriding the default.<br><br><b>--token &lt;token&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify a Vercel API token for authentication, useful for CI/CD environments.<br><br><b>--help, -h</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display help information for the current command or a specified subcommand.<br><br><b>--version, -v</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Output the current version of the Vercel CLI installed.<br><br><b>--debug</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable debug mode to show verbose output and detailed logs for troubleshooting.<br><br><b>--local-config &lt;path&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify a path to a custom <i>vercel.json</i> file for project-specific configuration.<br><br><b>--global-config &lt;path&gt;</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify a path to a custom global Vercel CLI configuration file.<br><br>


title: DESCRIPTION
content:
The <b>vercel</b> command-line interface (CLI) is the primary tool for interacting with the Vercel platform, a leading cloud platform for frontend developers. It enables rapid deployment of web projects, including static sites, Next.js applications, and serverless functions, to a global edge network. Users can deploy new versions of their applications instantly by simply running <b>vercel</b> from their project directory.<br><br>Beyond deployment, the CLI facilitates various management tasks such as linking projects, managing domains, viewing deployment logs, setting environment variables, and configuring project settings. A key feature is <b>vercel dev</b>, which provides a local development server that accurately mimics the Vercel production environment, ensuring consistency between local development and cloud deployment. The command streamlines the entire development workflow, from local testing to global deployment, leveraging Vercel's automatic scaling, SSL, and CDN capabilities for high performance and reliability with minimal configuration. It integrates seamlessly with popular Git providers, automating deployments on every push.


title: CAVEATS
content:
The <b>vercel</b> command requires an active Vercel account and stable internet connectivity for most operations, especially deployments. Authentication is primarily managed via <b>vercel login</b>, which typically involves an email verification process.<br><br>Users should be aware that project behavior can be heavily influenced by platform-specific configurations defined in a <i>vercel.json</i> file or derived from detected project frameworks. Certain commands or frequent deployments might be subject to Vercel's platform limits, depending on the user's account plan. It is primarily designed for projects intended to be hosted on the Vercel platform and is not a general-purpose deployment tool for arbitrary servers.


title: AUTOMATIC GIT INTEGRATION
content:
Vercel automatically integrates with Git repositories (GitHub, GitLab, Bitbucket) to enable continuous deployment. This means projects are automatically built and deployed to a preview URL on every push to a specified branch, and to production when pushing to the main branch.


title: PROJECT LINKING
content:
The <b>vercel link</b> command is crucial for associating a local directory with an existing Vercel project on the cloud. This ensures that subsequent <b>vercel</b> commands (like <b>vercel deploy</b> or <b>vercel env</b>) operate on the correct cloud project, maintaining consistency between your local development and the deployed application.


title: LOCAL DEVELOPMENT (VERCEL DEV)
content:
The <b>vercel dev</b> subcommand starts a local development server that accurately emulates the Vercel production environment. This includes correct routing, local invocation of serverless functions, and handling of environment variables, ensuring that your application behaves consistently during local development and after deployment.


title: HISTORY
content:
The Vercel platform, along with its CLI, was founded by Guillermo Rauch as Zeit in 2016. Initially gaining prominence for its focus on instant static deployments and serverless functions, the company rebranded to Vercel in 2020, emphasizing its role as 'The Frontend Cloud.'<br><br>Throughout its history, the <b>vercel</b> CLI has been central to the platform's user experience, evolving to support new features like <b>vercel dev</b> for local development, deeper integration with Git providers, and advanced project configurations. Its development has consistently aimed at simplifying the deployment and management of modern web applications, particularly those built with frameworks like Next.js, for which Vercel serves as the primary maintainer.


title: PARAMETERS
content:
<b><I>version1</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The first version string to compare. This should adhere to RPM's versioning format (e.g., <I>1.0</I>, <I>1.2.3-1.fc34</I>, <I>1:2.0</I>).<br><br><b><I>version2</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The second version string to compare against. This also should follow RPM's versioning conventions.<br><br>


title: DESCRIPTION
content:
<I>vercmp</I> is a utility typically found on RPM-based Linux distributions, used to compare two version strings according to the <B>RPM Package Manager's</B> versioning rules. This comparison logic is crucial for package management, determining which package version is "newer" for upgrades or dependency resolution. It returns an exit code indicating whether the first version is less than, equal to, or greater than the second. The comparison algorithm handles various versioning complexities including epochs, releases, pre-releases, and differing alphanumeric components, ensuring consistency with <B>RPM's</B> internal logic.


title: CAVEATS
content:
The comparison logic used by <B>vercmp</B> is specific to <B>RPM's</B> rules, which may differ significantly from other package managers (like <B>dpkg</B> on Debian/Ubuntu systems) or generic lexicographical or numeric sorting algorithms. It specifically handles:<ul><li><B>Epochs:</B> A numeric prefix followed by a colon (e.g., <I>1:2.0</I>). Epochs are compared numerically first.</li><li><B>Numerics:</B> Segments of digits are compared numerically. Trailing zeros within numeric segments are ignored (e.g., <I>1.0</I> is equal to <I>1</I>).</li><li><B>Alphabetics:</B> Segments of letters are compared lexicographically.</li><li><B>Tilde (~):</B> The tilde character often denotes a pre-release version, making it sort before a version without a tilde (e.g., <I>1.0~beta</I> < <I>1.0</I>).</li><li><B>Other Characters:</B> Other non-alphanumeric characters usually act as delimiters.</li></ul>


title: EXIT CODES
content:
The <B>vercmp</B> command communicates the comparison result through its exit code:<br><ul><li><b>0</b>: <I>version1</I> is equal to <I>version2</I>.</li><li><b>1</b>: <I>version1</I> is greater than <I>version2</I>.</li><li><b>2</b>: <I>version1</I> is less than <I>version2</I>.</li><li><b>3</b>: An error occurred (e.g., invalid arguments).</li></ul>


title: HISTORY
content:
<B>vercmp</B> emerged from the necessity of the <B>RPM Package Manager</B> to reliably determine version precedence for package upgrades and dependency resolution. It provides a standalone utility to externalize the same robust version comparison algorithm used internally by <B>rpm</B>, allowing developers and scripts to perform consistent version checks.


title: PARAMETERS
content:
<b><i>cert.pem ...</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;One or more X.509 certificate files to be verified. These are typically in PEM format.<br><br><b><b>-CAfile</b> <i>file</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a file containing trusted CA certificates (e.g., root CAs) used to build and verify the certificate chain.<br><br><b><b>-CApath</b> <i>directory</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a directory containing trusted CA certificates. Certificates in this directory must be hashed using <b>c_rehash</b> or <b>openssl rehash</b>.<br><br><b><b>-untrusted</b> <i>file</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a file containing untrusted certificates that may be part of the chain but are not considered trusted root CAs.<br><br><b><b>-crl_check</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables verification against Certificate Revocation Lists (CRLs) to ensure certificates in the chain have not been revoked. Requires CRLs to be available in the trusted store.<br><br><b><b>-purpose</b> <i>purpose</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Checks if the certificate is valid for a specific purpose (e.g., <i>sslclient</i>, <i>sslserver</i>, <i>email</i>). This enforces extended key usage constraints.<br><br><b><b>-verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provides detailed output during the verification process, showing each step and reason for success or failure.<br><br><b><b>-depth</b> <i>num</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the maximum verification depth, i.e., the maximum number of intermediate CA certificates that can be present in the chain.<br><br><b><b>-partial_chain</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Allows verification even if the full chain cannot be built up to a trusted root, verifying as much as possible.<br><br><b><b>-show_certs</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays the certificates in the chain found during verification, from the leaf certificate up to the trusted root.<br><br>


title: DESCRIPTION
content:
The <b>openssl verify</b> command is a crucial utility within the OpenSSL toolkit, designed for the rigorous validation of X.509 certificates and Certificate Revocation Lists (CRLs). Its primary function is to ascertain the trustworthiness of a given digital certificate by meticulously building and verifying its chain of trust, tracing it back to a securely trusted root certificate authority. Beyond just chain validation, the command is also capable of checking CRLs, an essential step to ensure that none of the certificates within the chain have been revoked due to compromise or other issues.<br><br>This versatile tool performs an array of vital checks, including cryptographic signature verification, assessment of certificate expiry dates, validation of basic constraints (such as whether a certificate is a CA), examination of key usage extensions, and adherence to name constraints. Through these comprehensive checks, <b>openssl verify</b> serves as a foundational component for securing communications and authenticating entities across a multitude of network protocols and applications, including but not limited to HTTPS, VPNs, and secure email systems. Its diligent use ensures the integrity, authenticity, and non-repudiation of digital identities in the digital landscape.


title: CAVEATS
content:
Successful verification heavily relies on a properly configured trust store (<b>-CAfile</b> or <b>-CApath</b>) with up-to-date and valid trusted CA certificates. For effective revocation checking, CRLs must be current. The command is sensitive to certificate expiry dates and cryptographic integrity; any issues will lead to verification failure. A solid understanding of X.509 certificate concepts is crucial for interpreting the results.


title: RETURN CODES
content:
The <b>openssl verify</b> command typically returns 0 upon successful verification of all certificates and a non-zero value if any certificate fails verification. This behavior is highly valuable for scripting and automated certificate validation processes.


title: TRUST STORE CONFIGURATION
content:
While <b>openssl verify</b> can leverage system-wide default paths for trusted CAs (e.g., <i>/etc/ssl/certs</i>), it is often best practice to explicitly specify the trusted certificate store using <b>-CAfile</b> or <b>-CApath</b> for specific verification tasks, ensuring control over the trust anchors.


title: HISTORY
content:
The <b>openssl</b> command suite, including <b>openssl verify</b>, is an integral part of the OpenSSL project, which originated in 1998 as a fork of the SSLeay library. It has continuously evolved, supporting new cryptographic standards, algorithms, and security features. <b>openssl verify</b> has been a fundamental component since early versions, undergoing regular updates to comply with evolving X.509 standards and to address new security challenges and vulnerabilities in certificate handling. Its persistent development highlights the ongoing necessity for robust cryptographic verification in the dynamic digital landscape.


title: PARAMETERS
content:
<b><b>--cc</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Generate C++ output code. This is the most common target language.<br><br><b><b>--sc</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Generate SystemC output code. Useful for integrating with SystemC verification environments.<br><br><b><b>--exe</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Link in a main_vlg.mk file and compile the generated code into an executable. Requires a C++ `main` function (e.g., `sim_main.cpp`) to be linked.<br><br><b><b>--build</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;After Verilator completes code generation, execute `make` on the generated files to compile the executable. This simplifies the build process.<br><br><b><b>-o</b> <i><name></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Name of the generated executable (when used with <b>--exe</b>).<br><br><b><b>-y</b> <i><dir></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Add directory to search path for Verilog includes/modules. Can be specified multiple times.<br><br><b><b>-I</b> <i><dir></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Equivalent to <b>-y</b> <i><dir></i>; adds a directory to the search path for Verilog files.<br><br><b><b>--trace</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable waveform tracing (VCD or FST format). Verilator generates code to dump signals, which can then be viewed with tools like GTKWave.<br><br><b><b>--trace-fst</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifically enables FST (Fast Signal Trace) format tracing, which is often more efficient than VCD for large designs.<br><br><b><b>--trace-max-array</b> <i><depth></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Limit the depth of arrays that will be traced. Useful to reduce trace file size.<br><br><b><b>--lint-only</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Only perform linting checks on the Verilog code; do not generate C++/SystemC output. Useful for static code analysis.<br><br><b><b>--Wno-</b><i><message_code></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Disable a specific warning message (e.g., <b>--Wno-UNOPTFLAT</b>).<br><br><b><b>--Werror-</b><i><message_code></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Treat a specific warning as an error (e.g., <b>--Werror-WIDTH</b>).<br><br><b><b>--top</b> <i><module_name></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the top-level module in the design. If not specified, Verilator attempts to infer it.<br><br><b><b>--Mdir</b> <i><dir></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Set the directory where generated C++/SystemC files and Makefiles will be placed. Defaults to `obj_dir`.<br><br><b><b>-CFLAGS</b> "<i><flags></i>"</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Add custom flags to the C++ compilation step (e.g., for optimization <b>-O3</b> or debugging <b>-g</b>).<br><br><b><b>-LDFLAGS</b> "<i><flags></i>"</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Add custom flags to the C++ linking step (e.g., for linking external libraries).<br><br>


title: DESCRIPTION
content:
<i>Verilator</i> is an open-source tool that converts Verilog/SystemVerilog HDL code into high-performance, cycle-accurate C++ or SystemC models. It compiles your HDL design directly into C++ (or SystemC), which is then compiled into an executable binary using a standard C++ compiler like GCC or Clang. This approach allows for very fast simulation speeds, often significantly quicker than traditional event-driven simulators, making it ideal for large-scale digital designs and CPU verification. <br><br>Beyond simulation, <i>Verilator</i> also functions as a robust linting tool, providing warnings and errors for common HDL design issues, Verilog specification violations, and potential synthesis problems, even if not generating executable code. It is widely used in hardware design and verification flows, especially for unit-level testing, co-simulation with C++ testbenches, and integrating hardware models into software development environments.


title: CAVEATS
content:
<i>Verilator</i> is a cycle-accurate simulator, not an event-driven one, which means it excels at fast, cycle-by-cycle execution but may not fully support all intricate timing models or SystemVerilog constructs (e.g., UVM, `bind`, `covergroup` assertions for formal verification) found in commercial simulators. Its focus is on synthesizable and behavioral RTL. Debugging happens at the C++/SystemC level, which can require different skills than typical HDL waveform debugging.


title: INTEGRATION WITH C++/SYSTEMC TESTBENCHES
content:
<i>Verilator</i>'s primary strength lies in its ability to integrate Verilog/SystemVerilog designs directly into a C++ or SystemC environment. This allows designers to write complex testbenches, verification components, and co-simulation scenarios using familiar programming languages, leveraging existing C++ libraries and debugging tools.


title: LINTING CAPABILITIES
content:
Even without generating simulation models, <i>Verilator</i> serves as an excellent linting tool. It can identify common design errors, potential synthesis mismatches, uninitialized signals, combinatorial loops, and other issues that might lead to unexpected hardware behavior or difficult-to-debug problems in later stages of the design flow. This makes it valuable for early-stage design analysis.


title: HISTORY
content:
Developed by Wilson Snyder, <i>Verilator</i> emerged as an open-source solution to address the need for high-performance simulation of Verilog designs. Its initial development focused on achieving speeds comparable to or exceeding proprietary simulators for cycle-accurate verification. Over the years, it has continuously evolved to support more SystemVerilog features and improve compilation efficiency, becoming a staple in various academic and industrial hardware verification workflows, particularly for FPGA and ASIC prototyping and pre-silicon validation.


title: SYNOPSIS
content:
<b>veritysetup</b> <I>command</I> [<I>options</I>] [<I>device</I>] [<I>arguments</I>]<br>Common commands:<br><b>veritysetup</b> <I>format</I> [--data-device=<I>data_dev</I>] [--hash-device=<I>hash_dev</I>] [<I>options</I>]<br><b>veritysetup</b> <I>open</I> [--data-device=<I>data_dev</I>] [--hash-device=<I>hash_dev</I>] <I>name</I> <I>hash_root</I> [<I>options</I>]<br><b>veritysetup</b> <I>close</I> <I>name</I>


title: PARAMETERS
content:
<b>--data-block-size=<bytes></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the block size (in bytes) for the data device. Must be a power of 2.<br><br><b>--hash-block-size=<bytes></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the block size (in bytes) for the hash device. Must be a power of 2.<br><br><b>--hash-algorithm=<algo></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Selects the cryptographic hash algorithm to use (e.g., <i>sha256</i>, <i>sha512</i>).<br><br><b>--salt=<hex_string></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provides an optional hexadecimal salt string to be used during hash tree generation.<br><br><b>--data-device=<path></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the path to the underlying data block device.<br><br><b>--hash-device=<path></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the path to the block device or file where the hash tree will be stored or read from.<br><br><b>--root-hash=<hex></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the expected root hash in hexadecimal format for opening or verifying the device.<br><br><b>--uuid=<UUID></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assigns a Universal Unique Identifier (UUID) to the verity device.<br><br>


title: DESCRIPTION
content:
<b>veritysetup</b> is a utility used to manage <i>dm-verity</i> devices, which provide authenticated integrity checking for block devices. It ensures that the contents of a block device have not been tampered with or corrupted. This is achieved by creating a cryptographic hash tree (a Merkle tree) over the entire data device. Each block's hash is stored in this tree, and a single root hash represents the integrity of the entire device.<br><br>When a <i>dm-verity</i> device is opened, the kernel uses the root hash to verify the integrity of data blocks as they are read. If any block's hash does not match the computed hash, an I/O error is reported, preventing the use of corrupt or malicious data. This makes <b>veritysetup</b> crucial for securing system partitions, especially in embedded systems and Android's Verified Boot, where verifying the integrity of the operating system is paramount. It provides a read-only view of the underlying data device.


title: CAVEATS
content:
<i>dm-verity</i> devices provide read-only access to the underlying data; write attempts will result in an I/O error.<br>The integrity guarantee relies entirely on the security and correctness of the root hash. If the root hash is compromised or incorrectly provided, the integrity check becomes unreliable.<br>While `<b>veritysetup</b>` ensures data integrity, it does not provide data encryption.


title: TYPICAL WORKFLOW
content:
A common workflow involves first using `<b>veritysetup format</b>` on a data device (e.g., a system partition) and storing the resulting root hash securely. Later, to access the device, `<b>veritysetup open</b>` is used with the data device, the hash device, and the securely stored root hash to create a read-only <i>dm-verity</i> mapped device. This mapped device can then be mounted like any other block device.


title: KERNEL MODULE DEPENDENCY
content:
The functionality of `<b>veritysetup</b>` relies on the Linux kernel's <i>dm-verity</i> module. This module must be loaded or compiled into the kernel for <i>dm-verity</i> devices to be recognized and managed by the operating system.


title: HISTORY
content:
The <i>dm-verity</i> device mapper target was introduced in the Linux kernel as a core component for ensuring system integrity, notably driven by Android's Verified Boot initiative (since Android 4.4 KitKat). `<b>veritysetup</b>` emerged as the user-space tool within the <i>cryptsetup</i> project to manage these <i>dm-verity</i> devices, providing functionalities like formatting a device with a verity tree and mapping a verity device for read-only access. Its development reflects the growing need for authenticated boot and system integrity verification in various Linux-based environments.


title: PARAMETERS
content:
<b><b>-a</b>, <b>--all</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display version information for all detected software and system components.<br><br><b><b>-k</b>, <b>--kernel</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Show detailed kernel version information.<br><br><b><b>-p</b> <I>package</I>, <b>--package=</b><I>package</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Show version information for a specific named package or application.<br><br><b><b>-s</b>, <b>--short</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Output a brief, summary-level report of version numbers only.<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Output detailed version information, including build details, commit hashes, and component dependencies.<br><br><b><b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display a help message and exit.<br><br><b><b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display the version information for the <b>version.1s</b> utility itself and exit.<br><br><b><I>SOFTWARE_NAME...</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify one or more software names (e.g., 'bash', 'nginx') for which to retrieve version information.<br><br>


title: DESCRIPTION
content:
The command &quot;<b>version.1s</b>&quot; is <I>not a standard Linux command</I> and does not exist in typical distributions. This analysis is therefore <I>hypothetical</I>, based on its name suggesting a utility for displaying version information.<br><br>If it were a real command, &quot;<b>version.1s</b>&quot; would likely provide comprehensive version details about installed software, system components, or the operating system itself. It would serve as a quick utility to ascertain the current state of various package versions, aiding in troubleshooting, compatibility checks, and system auditing. Its primary function would be to output a concise or detailed report of version numbers, build dates, and possibly license information for specified or all detected software. The unusual &quot;.1s&quot; suffix might suggest it's a custom shell script (where 's' stands for script) placed in the manual section for executable programs (section 1), or simply a unique naming convention for a specific project.


title: CAVEATS
content:
This command (&quot;<b>version.1s</b>&quot;) is <I>not a standard Linux command</I> and is not found in typical operating system installations. The analysis provided here is entirely <I>hypothetical</I>, constructed based on what such a command's name might imply.<br><br>Actual version-reporting on Linux is typically done using various commands depending on the component, such as <b>uname -a</b> for kernel, <b>lsb_release -a</b> or <b>cat /etc/os-release</b> for OS distribution, and package manager commands like <b>apt show &lt;package&gt;</b> (Debian/Ubuntu) or <b>rpm -q &lt;package&gt;</b> (Red Hat/Fedora), or directly querying application binaries with <b>&lt;command&gt; --version</b>.


title: UNUSUAL SUFFIX (.1S)
content:
The &quot;.1s&quot; suffix is highly unusual for standard Linux commands. Man pages are typically categorized by section number, e.g., <b>command(1)</b> for user commands, <b>command(8)</b> for administration commands. The &quot;s&quot; after the section number is non-standard. It <I>could</I> hypothetically imply a &quot;script&quot; (e.g., a shell script) intended to function as a user-level executable, but this is a speculation given its non-standard nature.


title: HISTORY
content:
Since &quot;<b>version.1s</b>&quot; is <I>not a standard Linux command</I>, it has no known official history or development timeline. If such a utility were to exist, its development would likely stem from the practical need for a unified interface to query software versions across diverse system components and package management systems. This would aim to streamline system auditing, dependency management, and troubleshooting, which traditionally require using multiple, disparate commands.


title: SYNOPSIS
content:
<i>vf</i> [<i>options</i>] [<i>path</i>]<br><br>Invoking <i>vf</i> without arguments starts the file manager in the current working directory. Optionally, a starting <i>path</i> can be provided.


title: PARAMETERS
content:
<b><i>path</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the initial directory to start the file manager in. If omitted, <i>vf</i> starts in the current working directory.<br><br><b>--help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a brief help message and exits.<br><br><b>--version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Shows the version information of the <i>vf</i> utility and exits.<br><br>


title: DESCRIPTION
content:
<i>vf</i> is a <b>fast</b>, interactive, and keyboard-driven file manager designed for command-line users. Written in Go, its primary goal is to provide an efficient way to navigate directories, quickly find files, and perform common file operations directly within the terminal.<br><br>It distinguishes itself by adopting a <i>vi</i>-like navigation paradigm, making it intuitive for users familiar with text editors like <i>Vim</i>. A <b>key feature</b> of <i>vf</i> is its reliance on external tools like <i>fzf</i> for powerful fuzzy-finding capabilities and <i>bat</i> for syntax-highlighted file previews, enhancing user experience without reinventing core functionalities.<br><br><i>vf</i> streamlines workflows by allowing users to seamlessly open selected files in their preferred text editor or pass them as arguments to other shell commands. Its design focuses on speed and minimalism, offering a highly responsive interface for efficient file management tasks, from browsing and searching to moving, copying, and deleting files.


title: CAVEATS
content:
<i>vf</i> is not a standard Linux command and needs to be installed separately. It relies heavily on external dependencies like <i>fzf</i> for fuzzy searching and <i>bat</i> for file previews; these must also be installed for <i>vf</i> to provide its full intended functionality. Its <i>vi</i>-like navigation means a learning curve for users unfamiliar with such keybindings.


title: DEPENDENCIES
content:
For optimal functionality, <i>vf</i> requires <i>fzf</i> for its fuzzy search feature and <i>bat</i> for rich file previews with syntax highlighting. Without these, core features will be missing or degraded.


title: KEYBINDINGS AND NAVIGATION
content:
<i>vf</i> operates primarily through keyboard shortcuts, leveraging a design philosophy inspired by <i>vi</i>. Users can expect common movement keys (h, j, k, l) and other operations to be familiar to Vim users. This focus on keyboard control allows for very rapid navigation and file manipulation.


title: INTEGRATION WITH EXTERNAL PROGRAMS
content:
A powerful aspect of <i>vf</i> is its ability to integrate with other command-line tools and text editors. Users can select files and directly open them in their preferred editor (e.g., <i>vim</i>, <i>code</i>) or pass the paths of selected files to custom shell commands for further processing.


title: HISTORY
content:
Developed by Kevin M. Smith, <i>vf</i> emerged around 2020 as a modern, keyboard-centric file manager written in Go. Its creation was motivated by a desire for a fast, terminal-based file management tool that integrates seamlessly with existing command-line utilities and embraces the efficiency of <i>vi</i>-like navigation. It builds upon the capabilities of tools like <i>fzf</i> and <i>bat</i>, which were gaining popularity at the time, offering a cohesive experience for power users.


title: DESCRIPTION
content:
The <b>vgcfgbackup</b> command is an essential LVM (Logical Volume Manager) utility designed to create a backup of the metadata associated with one or more LVM volume groups. LVM metadata contains crucial information about the structure and configuration of logical volumes, volume groups, and physical volumes. This includes details like logical volume names, sizes, physical extents mapping, and RAID configurations (if applicable). While many LVM operations automatically trigger a metadata backup, <b>vgcfgbackup</b> allows for manual, explicit backups. These backups are typically stored in <i>/etc/lvm/backup</i> (for the most recent state) and <i>/etc/lvm/archive</i> (for historical states). A clean and up-to-date metadata backup is paramount for disaster recovery, enabling the restoration of the LVM configuration using <b>vgcfgrestore</b> in case of corruption or accidental deletion of the original metadata on disk. Without accurate metadata, LVM volumes can become inaccessible, leading to data loss. Therefore, understanding and utilizing <b>vgcfgbackup</b> is a critical part of LVM system administration for ensuring data integrity and recoverability.


title: CAVEATS
content:
<ul><li>This command backs up only the LVM <i>metadata</i>, not the actual user <i>data</i> stored within the logical volumes. Data backups must be handled separately.</li><li>While <b>vgcfgbackup</b> can be run manually, most LVM commands (like <b>lvcreate</b>, <b>lvremove</b>, <b>vgextend</b>, etc.) usually perform automatic metadata backups before making changes.</li><li>The default backup directories (<i>/etc/lvm/backup</i> and <i>/etc/lvm/archive</i>) should be regularly backed up as part of your system's overall backup strategy.</li></ul>


title: AUTOMATIC BACKUPS
content:
Most LVM commands that modify LVM metadata (e.g., <b>lvcreate</b>, <b>lvremove</b>, <b>vgextend</b>) automatically trigger a metadata backup before applying changes. This provides an implicit safety net.


title: BACKUP LOCATIONS
content:
LVM metadata backups are typically stored in two directories:<br><i>/etc/lvm/backup</i>: Contains the most recent metadata backup for each volume group.<br><i>/etc/lvm/archive</i>: Stores historical copies of metadata backups, with each change generating a new dated archive file. The number of archived backups is configurable in <i>lvm.conf</i>.


title: CONFIGURATION FILE
content:
The behavior of LVM metadata backups (e.g., the number of archive copies to keep) can be configured in the <i>/etc/lvm/lvm.conf</i> file.


title: HISTORY
content:
<b>vgcfgbackup</b> is a fundamental component of LVM2 (Logical Volume Manager version 2), which superseded LVM1 and became the standard LVM implementation in Linux kernels starting around 2002-2003. LVM2 introduced significant improvements in scalability, flexibility, and robustness compared to its predecessor. The ability to explicitly back up LVM metadata, like with <b>vgcfgbackup</b>, has been a core feature since LVM2's inception, recognizing the critical importance of configuration metadata for system recovery and stability. Its design reflects the best practices for managing complex storage configurations, ensuring that administrators have the tools to recover from various failure scenarios.


title: SYNOPSIS
content:
<b>vgcfgrestore</b> [<i>OPTIONS</i>] <i>VolumeGroupName</i> [<b>-f</b> | <b>--file</b> <i>FileName</i>]


title: PARAMETERS
content:
<b><b>-f</b>, <b>--file</b> <i>&lt;FileName&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the path to the metadata archive file to be restored from. If omitted, <b>vgcfgrestore</b> searches the standard archive locations for the most recent backup for the given VG.<br><br><b><b>-l</b>, <b>--list-history</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Lists the metadata history of the specified Volume Group, showing available archive versions.<br><br><b><b>-t</b>, <b>--test</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Performs a dry run; <b>vgcfgrestore</b> will simulate the restoration process and report potential outcomes without making any actual changes to the system. This is highly recommended for safety.<br><br><b><b>-F</b>, <b>--force</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces the restoration even if inconsistencies or warnings are detected, such as when the metadata to be restored differs significantly from the current metadata. Use with extreme caution as it can lead to data loss.<br><br><b><b>--uuid</b> <i>&lt;UUID&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Restores the Volume Group using a specific UUID from its history. This is an advanced option typically used when multiple backups for a VG exist and a particular state needs to be restored.<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provides more detailed output during the restoration process, showing steps taken and potential issues.<br><br><b><b>-y</b>, <b>--yes</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assumes 'yes' to all prompts, allowing the command to proceed without requiring user confirmation.<br><br><b><b>-h</b>, <b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a help message with usage information and available options.<br><br><b><b>-V</b>, <b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Shows the version of the <b>vgcfgrestore</b> command.<br><br>


title: DESCRIPTION
content:
The <b>vgcfgrestore</b> command is a vital utility within the Logical Volume Manager (LVM) suite in Linux, designed to restore the metadata configuration of a Volume Group (VG) from a previously saved backup. LVM metadata stores crucial information about the structure of your logical volumes (LVs), physical volumes (PVs), and the volume group itself, including their sizes, names, and interconnections.<br><br>This command is primarily used in disaster recovery scenarios, such as when VG metadata becomes corrupted, is accidentally deleted, or if a VG needs to be reassembled on different physical disks. LVM automatically saves metadata backups in <i>/etc/lvm/archive</i> before most significant configuration changes, providing a safety net. Users can also manually create backups using <i>vgcfgbackup</i>.<br><br>When <b>vgcfgrestore</b> is executed, it reads the metadata from a specified archive file and attempts to apply it to the corresponding Volume Group. It's crucial that the underlying physical volumes (PVs) that comprised the VG at the time of the backup are present and accessible, as the command only restores metadata, not the data on the logical volumes themselves. Mismatched PV UUIDs or missing PVs can prevent a successful restore.<br><br>While powerful, <b>vgcfgrestore</b> must be used with extreme caution. Incorrect usage or restoring an unsuitable backup can lead to irreversible data loss or make your logical volumes inaccessible. It's often recommended to use the <i>--test</i> option first to preview the changes before committing them with <i>--force</i>.


title: CAVEATS
content:
<ul><li><b>Data Loss Risk</b>: Incorrectly using <i>vgcfgrestore</i>, especially with the <i>--force</i> option, can lead to irreversible data loss or render your logical volumes inaccessible. Always back up critical data before attempting a restore.</li><li><b>Metadata Only</b>: This command restores only the LVM metadata; it does <b>not</b> restore the actual data stored on your logical volumes. Your data remains untouched but might become inaccessible if the metadata is restored incorrectly.</li><li><b>Physical Volume Consistency</b>: For a successful restore, the underlying physical volumes (PVs) that were part of the Volume Group at the time the backup was created must be present, accessible, and their UUIDs must match. If PVs have been changed or replaced, recovery can be more complex.</li><li><b>LVM2 Format</b>: <i>vgcfgrestore</i> is part of the LVM2 suite and expects LVM2 metadata format. It cannot restore LVM1 metadata.</li><li><b>Read-Only Volume Groups</b>: A Volume Group must not be active or read-only when attempting to restore its configuration. You may need to deactivate it first (e.g., using <i>vgchange -an &lt;VGName&gt;</i>).</li></ul>


title: AUTOMATIC METADATA BACKUPS
content:
LVM automatically creates metadata backups in the <i>/etc/lvm/archive</i> directory (and sometimes <i>/etc/lvm/backup</i>) whenever significant changes are made to a Volume Group, such as creating or deleting logical volumes, or resizing them. These automatic backups are timestamped and are the primary source for <i>vgcfgrestore</i> if no specific file is provided.


title: METADATA ARCHIVE STRUCTURE
content:
The metadata archives are plain text files that describe the complete configuration of the Volume Group, including all its physical volumes, logical volumes, and their properties. While it's possible to inspect these files manually, it's generally not recommended to edit them directly due to the complexity and risk of corruption.


title: HISTORY
content:
<i>vgcfgrestore</i> is an integral part of the LVM2 (Logical Volume Manager version 2) suite, which became the standard LVM implementation in Linux kernels starting around 2.6. It evolved from the earlier LVM1 to provide more robust, flexible, and scalable storage management capabilities. The ability to restore metadata from backups was a critical feature designed into LVM2 from its inception, recognizing the importance of metadata integrity for storage reliability and disaster recovery. Its development has focused on enhancing reliability and providing finer control over restoration processes.


title: SEE ALSO
content:
<i>vgcfgbackup(8)</i>, <i>lvm(8)</i>, <i>vgchange(8)</i>, <i>vgdisplay(8)</i>, <i>lvcreate(8)</i>, <i>lvremove(8)</i>, <i>pvcreate(8)</i>, <i>pvremove(8)</i>


title: PARAMETERS
content:
<b>-a|--activate {y|n|{l|p|r}}</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Activates (y) or deactivates (n) volume groups. Options <i>l</i> (local), <i>p</i> (partial), <i>r</i> (read-only) provide more granular control over activation.<br><br><b>-d|--deactivate</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Deactivates volume groups (equivalent to <i>-a n</i>).<br><br><b>-K|--ignoreactivationskip</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Ignores the 'activation skipped' flag on a volume group, forcing activation.<br><br><b>-p|--partial</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Activates VGs with missing physical volumes (PVs), allowing access to remaining LVs. Use with caution as data might be incomplete.<br><br><b>-s|--scan</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Scans for all VGs on the system and refreshes LVM's cache without changing their state.<br><br><b>-t|--test</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Runs in test mode, showing what would happen without making actual changes to the system.<br><br><b>-v|--verbose</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provides verbose output, showing more details about the operations being performed.<br><br><b>--readonly</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the volume group to read-only mode, preventing writes to its logical volumes.<br><br><b>--readwrite</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the volume group to read-write mode, allowing writes.<br><br><b>--monitor {y|n}</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables (y) or disables (n) monitoring of the volume group by <i>lvmetad</i> for event handling.<br><br><b>--poll {y|n}</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables (y) or disables (n) polling for changes to the volume group, often used with monitoring.<br><br><b>--activationmode {partial|complete}</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Controls the activation mode for LVs, affecting how LVs are brought online if physical volumes are missing.<br><br><b>--noudevsync</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Disables <i>udev</i> synchronization after activation/deactivation. Use only if <i>udev</i> is not running or if issues arise.<br><br>


title: DESCRIPTION
content:
The <b>vgchange</b> command is a fundamental utility in Linux Logical Volume Management (LVM), used to modify the attributes of existing volume groups (VGs). Its primary function is to activate or deactivate VGs, making their logical volumes (LVs) accessible or inaccessible to the system. Activation is crucial for LVs to be mounted and used, while deactivation ensures data integrity before system shutdown or maintenance. Beyond activation, <b>vgchange</b> allows setting a VG to read-only or read-write, enabling monitoring, and managing tags. It is an essential command for managing the lifecycle and state of LVM storage components, particularly after system reboots, hardware changes, or during storage maintenance operations.


title: CAVEATS
content:
<b>Data Integrity</b>: Deactivating a volume group with active logical volumes can lead to data corruption. Always unmount file systems and stop applications accessing LVs before deactivation.<br><br><b>Partial Activation</b>: Using <i>-p</i> or <i>--activationmode partial</i> can activate LVs even if some underlying physical volumes are missing. While useful for recovery, it can expose incomplete data and should be used with extreme caution.<br><br><b>Cluster Environments</b>: In clustered LVM setups (CLVM), <b>vgchange</b> must be used with care to ensure consistent state across nodes and avoid split-brain scenarios. Proper locking mechanisms are critical.<br><br><b>udev Synchronization</b>: <b>vgchange</b> typically synchronizes with <i>udev</i> to ensure device nodes are correctly created or removed. Disabling this with <i>--noudevsync</i> can lead to stale or missing device nodes.


title: ACTIVATION MODES
content:
The <i>--activationmode</i> option (e.g., <i>partial</i>, <i>complete</i>) offers fine-grained control over how logical volumes within a VG are activated when not all physical volumes are available. This is crucial for managing degraded arrays or performing recovery operations.


title: LVMETAD INTERACTION
content:
<b>vgchange</b> often interacts with <i>lvmetad</i>, the LVM metadata daemon. Options like <i>--monitor</i> and <i>--poll</i> control how <b>vgchange</b> communicates with <i>lvmetad</i> to manage VG metadata caching and event handling, improving performance and responsiveness in dynamic LVM environments.


title: HISTORY
content:
<b>vgchange</b> is an integral part of the Logical Volume Manager (LVM) framework, which has been a core component of Linux kernel distributions for managing storage since its introduction in the late 1990s. The command's functionality, particularly for activating and deactivating volume groups, has remained central to LVM's operation since its inception. Over time, LVM and <b>vgchange</b> have evolved to support advanced features like snapshots, mirroring, striping, and more robust clustering capabilities, with options like <i>--monitor</i> and <i>--activationmode</i> being added to address modern storage requirements and improve system resilience. Its continuous development reflects the ongoing need for flexible and dynamic storage management in Linux systems.


title: SEE ALSO
content:
pvcreate(8), vgcreate(8), lvcreate(8), vgdisplay(8), lvdisplay(8), vgscan(8), lvscan(8), vgremove(8), lvs(8), vgs(8)


title: PARAMETERS
content:
<b><b>-a</b>, <b>--all</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Check all known volume groups on the system.<br><br><b><b>-A</b>, <b>--autocorrect</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Attempt to automatically correct detected metadata errors. <i>Use with extreme caution, as this can lead to data loss if used improperly.</i><br><br><b><b>-l</b>, <b>--long</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display detailed information about any inconsistencies found, providing more context than the default output.<br><br><b><b>-s</b>, <b>--summary</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Print only a summary of the check results for each volume group, indicating whether inconsistencies were found.<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provide more detailed output during the check process, showing progress and additional information.<br><br><b><b>--ignore-errors</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Continue processing even if metadata errors are encountered, rather than stopping on the first error.<br><br>


title: DESCRIPTION
content:
<b>vgck</b> is a utility from the LVM (Logical Volume Manager) suite used to check the consistency of LVM metadata for one or more specified volume groups (VGs), or all VGs if none are specified.<br><br>It performs various checks on the LVM metadata located on physical volumes (PVs) that constitute the volume group. This command is primarily used for diagnostic purposes, helping administrators identify potential corruption or inconsistencies in the LVM configuration. It reports errors or warnings but does not, by default, attempt to fix them. The output can include details about missing PVs, corrupted metadata, or other structural issues. It's an essential tool for maintaining the integrity of an LVM setup, especially when troubleshooting LVM-related problems or after system crashes.


title: CAVEATS
content:
By default, <b>vgck</b> is a non-destructive command. However, the <b>--autocorrect</b> option can make permanent changes to LVM metadata, which could lead to data loss or further corruption if used improperly or without a clear understanding of the reported issues. It is always highly recommended to back up LVM metadata using <b>vgcfgbackup</b> before attempting any automatic corrections. Running <b>vgck</b> on very large or complex LVM setups can be time-consuming due to the extensive metadata checks.


title: HISTORY
content:
<b>vgck</b> is an integral part of the LVM2 suite, which is the standard Logical Volume Manager implementation for Linux systems since the early 2000s. LVM provides a layer of abstraction over physical storage devices, allowing for more flexible storage management. <b>vgck</b> evolved as a crucial diagnostic tool within this framework to ensure the integrity and consistency of the metadata that describes the volume groups, logical volumes, and physical volumes. Its development parallels the ongoing enhancements and stability efforts within the broader LVM project, aiming to provide robust storage management capabilities for Linux.


title: SYNOPSIS
content:
<code>vgconvert [-s|--setversion <I>Version</I>] [-M|--metadatacopies <I>Number</I>] [COMMON_OPTIONS] <I>VolumeGroupName</I>...</code>


title: PARAMETERS
content:
<b>-s <I>version</I>, --setversion <I>version</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the metadata format version (e.g., '1' for LVM1, '2' for LVM2).<br><br><b>-M <I>number</I>, --metadatacopies <I>number</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the number of metadata copies to store on each Physical Volume.<br><br><b>-f, --force</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Force the operation, overriding certain checks. Use with caution.<br><br><b>-y, --yes</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assume 'yes' to all questions; bypasses interactive prompts.<br><br><b>-v, --verbose</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable verbose output, showing detailed runtime information.<br><br><b>-h, --help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display a help message and exit.<br><br><b>-V, --version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Show program version information and exit.<br><br><b><I>VolumeGroupName</I>...</b><br>&nbsp;&nbsp;&nbsp;&nbsp;One or more names of the Volume Groups to be converted.<br><br>


title: DESCRIPTION
content:
The `vgconvert` command in Linux LVM (Logical Volume Manager) is used to change the metadata format of an existing volume group. Its primary historical use was to migrate volume groups from the older LVM1 metadata format to the more advanced and feature-rich LVM2 format. While LVM2 is now the default and widely adopted standard, `vgconvert` remains useful for ensuring compatibility or adjusting metadata properties like the number of metadata copies stored on physical volumes. For a successful conversion, the target volume group must be inactive, meaning no logical volumes within it are in use. This command is a critical tool for LVM administrators managing evolving storage infrastructures or integrating older LVM setups with modern systems. It allows for an in-place upgrade of the metadata structure, unlocking new features and improving resilience.


title: CAVEATS
content:
The target volume group must be <b>inactive</b> before running `vgconvert` (e.g., using `vgchange -an <I>VolumeGroupName</I>`).<br>Converting to a newer LVM format (e.g., LVM2) might render the volume group inaccessible on older systems running LVM1-only kernels or utilities.<br>Always <b>back up LVM metadata</b> using `vgcfgbackup` before performing any metadata conversions or modifications.


title: INACTIVE VOLUME GROUP REQUIREMENT
content:
For `vgconvert` to operate successfully, the target volume group must be in an inactive state. This ensures that no logical volumes within the group are in use or mounted, preventing data corruption during the metadata conversion process. Use `vgchange -an <I>VolumeGroupName</I>` to deactivate it prior to conversion and `vgchange -ay <I>VolumeGroupName</I>` to reactivate it afterward.


title: METADATA BACKUP RECOMMENDATION
content:
Before performing any potentially disruptive operations like metadata conversions, it is highly recommended to back up your LVM metadata. The `vgcfgbackup` command can be used for this purpose. In case of unforeseen issues, metadata can be restored using `vgcfgrestore`, mitigating data loss.


title: HISTORY
content:
`vgconvert` gained prominence during the transition from the original LVM (often called LVM1) to LVM2. LVM2 introduced significant improvements in scalability, flexibility, and features. This command was crucial for administrators to update their existing LVM1 volume groups to the LVM2 metadata format, enabling them to leverage the new capabilities without recreating their storage infrastructure. While new LVM deployments now default to LVM2, `vgconvert` remains an essential tool for maintaining and ensuring compatibility of legacy LVM setups.


title: SYNOPSIS
content:
<b>vgcreate</b> [<i>OPTIONS</i>] <i>VolumeGroupName</i> <i>PhysicalVolumePath</i> [<i>PhysicalVolumePath</i>...]<br>


title: PARAMETERS
content:
<b>-s, --physicalextentsize <i>Size</i>[B|K|M|G|T|P|E]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the size of physical extents for the new volume group. This is a crucial setting as all logical volumes within the VG will be allocated in multiples of this size. The default is 4MiB.<br><br><b>-c, --clustered {y|n}</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Configures the volume group for use in a clustered LVM environment. Set to 'y' for clustered setups.<br><br><b>-l, --maxlogicalvolumes <i>Number</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the maximum number of logical volumes that can be created in this volume group. A value of 0 means no limit. Defaults to 0.<br><br><b>-p, --maxphysicalvolumes <i>Number</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the maximum number of physical volumes that can be added to this volume group. A value of 0 means no limit. Defaults to 0.<br><br><b>-A, --autobackup {y|n}</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Controls automatic metadata backup for the volume group. 'y' (default) enables automatic backup to /etc/lvm/backup, 'n' disables it.<br><br><b>-f, --force</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces the creation of the volume group, even if it appears unsafe or if the physical volumes already contain LVM metadata. Use with caution as it can overwrite existing data.<br><br><b>-y, --yes</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assumes 'yes' to all questions; useful for scripting.<br><br><b>-v, --verbose</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Increases verbose output, showing more details about the command execution.<br><br><b>--addtag <i>Tag</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Adds a tag to the newly created volume group. Tags are arbitrary strings that can be used to group and filter LVM objects.<br><br><b>--metadatasize <i>Size</i>[B|K|M|G|T|P|E]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the size of the metadata area on the physical volume(s). This is rarely needed as LVM usually handles it automatically.<br><br><b>--pvmetadatacopies <i>Number</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the number of copies of LVM metadata to store on each physical volume. Default is 1 or 2, depending on the metadata area type.<br><br><b>--systemid <i>SystemID</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assigns a unique system ID to the volume group. This is relevant in environments where VGs might be shared or moved between systems.<br><br><b>--readonly</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Creates the volume group in a read-only state. This prevents any writes to the volume group or its logical volumes.<br><br>


title: DESCRIPTION
content:
<i>vgcreate</i> is a fundamental command in Logical Volume Management (LVM) on Linux systems. It is used to create a new volume group (VG) from one or more physical volumes (PVs). A volume group acts as a container for logical volumes (LVs) and aggregates the storage space from multiple physical volumes, allowing for flexible storage management, including resizing, snapshotting, and striping. Before creating a VG, you must first initialize physical volumes using <i>pvcreate</i>. <i>vgcreate</i> takes the name of the new volume group and the names of the physical volumes to include. Once created, logical volumes can be allocated from the VG's free space using <i>lvcreate</i>. The command writes LVM metadata to the specified physical volumes, marking them as part of the new volume group.


title: CAVEATS
content:
<b>Important Considerations:</b><br>1. Before creating a volume group, the underlying devices must first be initialized as physical volumes using the <i>pvcreate</i> command.<br>2. Ensure that the chosen physical volumes have sufficient free space and are not already part of another active LVM volume group (unless using <i>--force</i>, which is not recommended without understanding the risks).<br>3. The <i>VolumeGroupName</i> must be unique on the system and adhere to LVM naming conventions.<br>4. Using the <i>--force</i> option can lead to data loss if used incorrectly, as it can overwrite existing LVM metadata or other filesystem structures.<br>


title: LVM HIERARCHY
content:
LVM organizes storage in a three-tier hierarchy:<br>1. <b>Physical Volumes (PVs)</b>: These are physical disk partitions or entire disks initialized for LVM use via <i>pvcreate</i>.<br>2. <b>Volume Groups (VGs)</b>: Created using <i>vgcreate</i>, VGs aggregate one or more PVs into a single storage pool.<br>3. <b>Logical Volumes (LVs)</b>: Created using <i>lvcreate</i>, LVs are virtual partitions carved out of a VG's free space. Filesystems are then created on LVs.


title: VOLUME GROUP NAMING
content:
When choosing a <i>VolumeGroupName</i>, it is best practice to use descriptive names (e.g., 'vg_data', 'vg_root'). Names should typically consist of alphanumeric characters, hyphens, and underscores, avoiding spaces or special characters. They must be unique across the system.


title: HISTORY
content:
<i>vgcreate</i>, along with other core LVM commands, has been a cornerstone of Linux's Logical Volume Manager since its early development. LVM (specifically LVM2, which is the current mainstream version) evolved to provide more robust and flexible storage management capabilities than traditional fixed-size partitions. The command's fundamental function of aggregating physical storage into logical units has remained consistent, adapting to new storage technologies and requirements like clustering and thin provisioning over time.


title: SYNOPSIS
content:
<code><b>vgdisplay</b> [<i>OPTIONS</i>] [<i>VolumeGroupName</i>...]</code><br><br>Displays detailed information about LVM volume groups. If <i>VolumeGroupName</i> is omitted, information for all volume groups is shown.


title: PARAMETERS
content:
<b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Enables verbose output, showing more details about the volume group, including information about contained physical and logical volumes.</i><br><br><b><b>-C</b>, <b>--colon</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Generates colon-separated output. This format is designed to be easily parseable by scripts and other programs.</i><br><br><b><b>-s</b>, <b>--short</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Displays a short summary of volume groups, providing a less detailed overview than the default or verbose modes.</i><br><br><b><b>-o</b> <<i>fields</i>>, <b>--options</b> <<i>fields</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Specifies a comma-separated list of fields to display. This allows users to customize the output to show only specific attributes (e.g., 'vg_name,vg_size,vg_free').</i><br><br><b><b>--units</b> <<i>units</i>></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>Specifies the units for displayed sizes. Common units include 'b' (bytes), 'k' (kilobytes), 'm' (megabytes), 'g' (gigabytes), 't' (terabytes), 'p' (petabytes), 'e' (exabytes).</i><br><br><b><i>VolumeGroupName...</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<i>One or more specific volume group names to display information for. If omitted, <b>vgdisplay</b> shows information for all active volume groups on the system.</i><br><br>


title: DESCRIPTION
content:
The <b>vgdisplay</b> command is a fundamental utility within the Logical Volume Manager (LVM) framework on Linux systems. It is used to present comprehensive information about <i>volume groups</i> (VGs). A volume group is a storage pool composed of one or more physical volumes (PVs), from which logical volumes (LVs) are carved out.<br><br>When executed, <b>vgdisplay</b> provides a detailed overview of a specified volume group or all volume groups if none are specified. This includes critical metrics such as the VG's size, the amount of free space available, the number of physical volumes it contains, the number of logical volumes derived from it, and various metadata attributes like VG UUID, allocation policy, and more. It's an essential command for system administrators to monitor, plan, and troubleshoot LVM storage configurations, as it offers a read-only snapshot of the current state of VGs.


title: CAVEATS
content:
<b>Caveats</b>: <b>vgdisplay</b> is a <b>read-only</b> command; it does not modify the LVM configuration or data.<br>Full detailed output (especially with <b>-v</b>) can be extensive, making it suitable for in-depth analysis rather than quick checks.<br>Requires appropriate user permissions (typically <b>root</b> or via <b>sudo</b>) to access LVM metadata and display all system-wide volume groups.


title: COMPARISON WITH <B>VGS</B>
content:
While <b>vgdisplay</b> provides comprehensive, multi-line output for detailed analysis of volume groups, the <b>vgs</b> command offers a concise, one-line summary of volume group information. For quick checks of free space, size, and PV/LV counts, <b>vgs</b> is often preferred due to its brevity, whereas <b>vgdisplay</b> is used for in-depth inspection and troubleshooting.


title: UNDERSTANDING OUTPUT FIELDS
content:
The output of <b>vgdisplay</b> typically includes numerous fields. Key fields include: <i>VG Name</i> (the name of the volume group), <i>VG Size</i> (total capacity), <i>VG Free</i> (available space), <i>PE Size</i> (Physical Extent size, the smallest unit of allocation), <i>Total PE</i> and <i>Alloc PE / Free PE</i> (counts of physical extents). Understanding these fields is crucial for managing LVM storage effectively.


title: HISTORY
content:
The <b>vgdisplay</b> command is an integral part of the Logical Volume Manager (LVM) framework, which was first introduced into the Linux kernel in version 2.4. LVM provides an abstraction layer over physical storage devices, allowing for flexible storage management. <b>vgdisplay</b> has been a core utility since the early days of LVM, evolving with the LVM feature set to provide increasingly comprehensive views of volume group attributes. Its fundamental purpose—displaying VG details—has remained consistent, making it a cornerstone for LVM administration.


title: SYNOPSIS
content:
<b>vgexport</b> [<I>options</I>] <I>VolumeGroupName</I>...<br><b>vgexport</b> <b>-a</b>|<b>--all</b> [<I>options</I>]


title: PARAMETERS
content:
<b><b>-a</b>, <b>--all</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Exports all volume groups that are currently deactivated.<br><br><b><b>-p</b>, <b>--partial</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Allows export of a volume group even if some of its physical volumes are missing. Use with caution.<br><br><b><b>-t</b>, <b>--test</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Runs the command in test mode, showing what would happen without actually making any changes.<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provides more detailed output during command execution.<br><br><b><b>-h</b>, <b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a help message and exits.<br><br><b><b>-V</b>, <b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays the LVM version information and exits.<br><br><b><I>VolumeGroupName</I>...</b><br>&nbsp;&nbsp;&nbsp;&nbsp;The name(s) of the volume group(s) to be exported. Multiple names can be specified.<br><br>


title: DESCRIPTION
content:
The <b>vgexport</b> command is part of the <I>Logical Volume Manager (LVM)</I> suite of utilities. It serves the crucial purpose of making one or more volume groups (VGs) inaccessible and unknown to the operating system. When a volume group is exported, LVM removes its metadata from the kernel's device mapper, effectively unregistering the VG. This action does not delete any data on the physical volumes comprising the volume group; it merely makes the VG unavailable for use by the system.<br><br>This command is typically used in scenarios where a volume group needs to be moved from one system to another, or when it needs to be temporarily or permanently removed from the current system's active LVM configuration without destroying the underlying data. Before a volume group can be exported, it is imperative that all its logical volumes are closed and the volume group itself is deactivated (e.g., using <b>vgchange -an <I>VolumeGroupName</I></b>). Exporting an active volume group is not permitted by LVM to prevent data corruption. After export, the physical volumes belonging to the VG are free to be moved to another system, where they can be re-registered using the <b>vgimport</b> command.


title: CAVEATS
content:
Before exporting a volume group, ensure that all its logical volumes are unmounted and closed, and the volume group itself is deactivated using <b>vgchange -an <I>VolumeGroupName</I></b>. Attempting to export an active volume group will result in an error.<br><br><b>vgexport</b> does not delete any data on the physical volumes. It only removes the volume group's metadata from the system's active LVM configuration. The data remains intact on the physical disks.<br><br>When dealing with shared storage, ensure proper fencing or coordination to prevent other systems from accessing or attempting to import the same volume group concurrently, which could lead to data corruption.


title: USE CASES FOR MIGRATION
content:
<b>vgexport</b> is indispensable for migrating volume groups between different systems. After deactivating and exporting a VG from a source machine, its underlying physical volumes can be physically moved or presented via a SAN to a target machine. On the target, <b>vgimport</b> is then used to re-register the VG, making its logical volumes accessible.


title: TROUBLESHOOTING AND RECOVERY
content:
In some advanced troubleshooting scenarios, if a volume group's metadata becomes corrupted or inaccessible on a system, exporting it (if possible) and then re-importing it might help refresh the LVM's view of the VG. This assumes the underlying physical volume metadata remains intact.


title: HISTORY
content:
The <b>vgexport</b> command has been a fundamental part of the <I>Logical Volume Manager (LVM)</I> suite since its early iterations on Linux. LVM, first introduced to the Linux kernel around 1998, provided a flexible way to manage disk space. <b>vgexport</b>'s role has consistently been to facilitate the removal and portability of volume groups, making it a critical tool for system administrators needing to migrate storage, perform hardware maintenance, or decommission systems. Its core functionality has remained stable, evolving primarily with improvements and bug fixes within the broader LVM framework.


title: SYNOPSIS
content:
<b>vgextend</b> [<i>OPTIONS</i>] <i>VolumeGroupName PhysicalVolumePath</i> [<i>PhysicalVolumePath</i>...]


title: PARAMETERS
content:
<b><b>-f</b>, <b>--force</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Force the operation, overriding certain checks or warnings.<br><br><b><b>-t</b>, <b>--test</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Perform a dry run; do not make any actual changes. Useful for testing commands without risk.<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display detailed runtime information, showing more of what the command is doing.<br><br><b><b>-y</b>, <b>--yes</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assume "yes" to all questions; useful for scripting interactive commands.<br><br><b><b>--addtag</b> <i>&lt;tag&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Add a tag to the volume group being extended.<br><br><b><b>--alloc</b> <i>&lt;policy&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the allocation policy for physical extents (e.g., <i>contiguous</i>, <i>anywhere</i>, <i>cluster</i>).<br><br><b><b>--config</b> <i>&lt;config_string&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Use a specific configuration string for this command execution.<br><br><b><b>--devices</b> <i>&lt;devices_list&gt;</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Restrict the scan and operation to specified devices only.<br><br><b><b>--noudevsync</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Do not synchronize with udev. This may cause problems if udev is not aware of the changes.<br><br>


title: DESCRIPTION
content:
<b>vgextend</b> is a crucial command in Linux's Logical Volume Manager (LVM) framework, designed to expand the storage capacity of an existing volume group. A volume group (VG) is a collection of one or more physical volumes (PVs), which are typically disk partitions or entire disks. When a volume group's available space becomes insufficient, <b>vgextend</b> allows administrators to incorporate additional PVs, thereby increasing the total pool of storage from which logical volumes (LVs) can be allocated.<br><br>Before using <b>vgextend</b>, any new physical devices intended for addition must first be initialized as LVM physical volumes using the <b>pvcreate</b> command. Once prepared, <b>vgextend</b> seamlessly integrates these PVs into the specified volume group, making their storage available. This dynamic resizing capability is a cornerstone of LVM, providing flexibility to adapt storage infrastructure without downtime (for the VG operation itself). It's important to note that extending a volume group only increases the overall capacity; it does not automatically extend any existing logical volumes within that group. Logical volumes must be extended separately using the <b>lvextend</b> command.


title: CAVEATS
content:
<ul><li>Adding PVs to a VG increases its capacity, but does <i>not</i> automatically extend existing Logical Volumes (LVs). LVs must be extended separately using <b>lvextend</b>.</li><li>The Physical Volumes (PVs) being added must first be initialized using <b>pvcreate</b> and must <i>not</i> already be part of another volume group.</li><li><b>vgextend</b> requires root privileges to execute successfully.</li><li>Ensure the PVs are healthy and accessible before attempting to add them to a volume group.</li></ul>


title: PREREQUISITES
content:
Before a physical device (like a disk or partition) can be added to a volume group using <b>vgextend</b>, it must first be prepared as an LVM Physical Volume. This preparation is done using the <b>pvcreate</b> command, which initializes the device by writing LVM metadata to it.


title: CAPACITY VS. LV SIZE
content:
While <b>vgextend</b> increases the overall storage capacity of the volume group, it is crucial to understand that this does not automatically resize any existing logical volumes within that group. The newly added space becomes available for creating new logical volumes or for extending existing ones with <b>lvextend</b>.


title: HISTORY
content:
The Logical Volume Manager (LVM) for Linux was largely inspired by the LVM implementation found in HP-UX, with initial work beginning in the late 1990s and significant adoption in the early 2000s. <b>vgextend</b> has been a core component of the LVM suite since its early versions, providing the essential capability to dynamically grow storage pools. Its functionality reflects the fundamental need for flexible, scalable storage management in enterprise and general-purpose Linux environments, allowing system administrators to adapt storage capacity on the fly without complex reconfigurations or service interruptions.


title: PARAMETERS
content:
<b><i>VG_NAME</i>...</b><br>&nbsp;&nbsp;&nbsp;&nbsp;The name(s) of the Volume Group(s) to be imported. Multiple VG names can be specified.<br><br><b>-a, --all</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Import all exported Volume Groups found by scanning the system's physical volumes.<br><br><b>-d, --debug</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable verbose debugging messages during the import process, useful for troubleshooting.<br><br><b>-h, --help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display a brief help message and exit, showing command usage and options.<br><br><b>-v, --verbose</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enable verbose messages, providing more detailed output about the import operation.<br><br>


title: DESCRIPTION
content:
The <b>vgimport</b> command is used to make an LVM (Logical Volume Manager) Volume Group (VG) known to the current system. This operation involves reading the LVM metadata from the physical volumes (PVs) that constitute the specified VG and adding it to the system's LVM cache. It is a critical command for various scenarios, including recovering a VG whose metadata might have been lost or corrupted, re-adding a VG that was previously exported using <b>vgexport</b> for migration purposes, or making a VG from a different system accessible.<br><br>While <b>vgimport</b> makes the VG visible to the LVM daemon, it does not automatically activate its logical volumes (LVs). After importing, it's typically necessary to activate the LVs using commands like <b>vgchange -a y <i>VG_NAME</i></b> or <b>lvchange -a y <i>VG_NAME</i>/<i>LV_NAME</i></b> to make them accessible for mounting or other operations. It is essential that all physical volumes belonging to the VG are present and accessible by the system for a successful import operation.


title: CAVEATS
content:
<b>vgimport</b> only makes the Volume Group known to the system; it does not automatically activate its Logical Volumes. Manual activation using <b>vgchange -a y</b> or <b>lvchange -a y</b> is usually required afterward.<br>All physical volumes (PVs) belonging to the Volume Group must be present and accessible by the system for the import to succeed.<br>Ensure that the VG name is unique on the system if importing a VG from another system to avoid potential naming conflicts.


title: TYPICAL USAGE SCENARIOS
content:
<b>vgimport</b> is commonly used in several key scenarios:<br>1. <i>Migrating VGs:</i> After exporting a VG from one system using <b>vgexport</b>, it can be imported to another system.<br>2. <i>System Recovery:</i> If LVM metadata on the system's cache or configuration files becomes corrupted or is accidentally deleted, <b>vgimport</b> can rebuild the VG's knowledge from the metadata on the physical volumes.<br>3. <i>Adding Pre-existing VGs:</i> When connecting disks containing LVM VGs from another system, <b>vgimport</b> makes them recognized and usable by the new system.


title: HISTORY
content:
The <b>vgimport</b> command is an integral part of the LVM2 (Logical Volume Manager version 2) suite, which represents a significant evolution in Linux's storage management capabilities. Its development, alongside other LVM commands, aimed at providing robust, flexible, and portable methods for managing disk partitions.<br><br>The concept of importing and exporting Volume Groups was introduced to facilitate the migration of storage between systems or to manage shared storage arrays, enhancing the portability of LVM configurations. Its usage is fundamental in disaster recovery scenarios and system migrations, ensuring that LVM metadata, which resides on the physical volumes themselves, can be re-integrated into a system's active LVM configuration reliably. It has been a stable component of LVM2 since its inception, continually refined to ensure metadata consistency and system stability.


title: PARAMETERS
content:
<b><i>PhysicalVolumePath</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The path(s) to the physical volume(s) that belong to the cloned Volume Group (e.g., <i>/dev/sdb</i>, <i>/dev/mapper/mpatha</i>).<br><br><b><b>-n</b> <i><new_vg_name></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a new name for the imported Volume Group. This is highly recommended to avoid naming conflicts if the original VG name is already present or desired to be different.<br><br><b><b>--force</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Proceeds with the operation without requiring interactive confirmation, overriding some warnings. Use with extreme caution.<br><br><b><b>--basevg</b> <i><original_vg_name></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;When used with <b>-n</b>, this option allows specifying an original VG name, and the new VG name will be derived from it (e.g., <i>original_vg_new</i>).<br><br><b><b>--nouuidcheck</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Skips the check for UUID uniqueness. <b><i>Use with extreme caution</i></b>, as this can lead to UUID conflicts if not properly managed, potentially corrupting metadata.<br><br><b><b>--restorefile</b> <i><file></i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Imports the Volume Group using metadata from a specified backup file instead of directly from the PVs. Useful for recovering from metadata corruption or specific scenarios.<br><br>


title: DESCRIPTION
content:
<i><b>vgimportclone</b></i> is a crucial LVM utility designed to handle situations where LVM Volume Groups (VGs) have been duplicated, typically through disk imaging or virtual machine cloning. When a disk containing an LVM VG is cloned, the resulting copy will have an identical VG Unique Identifier (UUID) to the original. If both the original and the cloned disks are presented to the same system, this UUID conflict can prevent the system from properly activating or distinguishing between the VGs, potentially leading to data corruption or inaccessible logical volumes.<br><br>The primary function of <i><b>vgimportclone</b></i> is to scan the specified Physical Volumes (PVs) for LVM metadata, detect duplicated VG UUIDs, and then assign a <b>new, unique UUID</b> to the cloned Volume Group. It also provides options to rename the VG during the import process, ensuring that the cloned VG can coexist with the original or be independently managed on the system. This command is indispensable for maintaining LVM integrity in complex storage environments.


title: CAVEATS
content:
Using <i><b>vgimportclone</b></i> incorrectly can lead to <b><i>irreversible data loss or corruption</i></b>. Always ensure you are targeting the correct physical volumes. It is highly recommended to perform an LVM metadata backup (e.g., using <i>vgcfgbackup</i>) before running this command. If the original Volume Group is still active and accessible on the system, ensure it is deactivated or exported before attempting to import a cloned VG with the same UUID to prevent conflicts and potential data integrity issues.


title: TYPICAL USAGE SCENARIO
content:
A common use case involves cloning a virtual machine disk. When the cloned VM is started, its disk's LVM Volume Group will have the same UUID as the original. If both VMs are running on the same host or you're trying to attach the cloned disk to another system, <i><b>vgimportclone</b></i> is used to resolve this conflict. The general steps are:<br><br>1. Attach the cloned physical disk(s) to the system.<br>2. Run <i><b>pvscan</b></i> and <i><b>vgscan</b></i>; you might see warnings about duplicate UUIDs.<br>3. Execute <i><b>vgimportclone</b></i>, specifying the cloned PVs and a new VG name: <i><b>vgimportclone -n <new_vg_name> /dev/sdX</b></i> (or appropriate PV paths).<br>4. After successful import, the new VG can be activated: <i><b>vgchange -ay <new_vg_name></b></i>.<br>5. The logical volumes can then be mounted.


title: HISTORY
content:
<i><b>vgimportclone</b></i> is an integral part of the LVM2 suite, which represents the second generation of Linux Logical Volume Manager. LVM2, introduced to improve upon LVM1, brought significant enhancements in metadata handling, scalability, and robustness. The inclusion of commands like <i><b>vgimportclone</b></i> addresses complex scenarios such as disk cloning and migration, providing tools to manage LVM metadata conflicts that were less straightforward in earlier versions. Its development reflects the increasing need for flexible and resilient storage management in virtualized and cloud environments.


title: SYNOPSIS
content:
<b>vgmerge</b> [-f|--force] [--noudevsync] [--reportformat {basic|json}] <i>SourceVG</i> <i>TargetVG</i>


title: PARAMETERS
content:
<b>SourceVG</b><br>&nbsp;&nbsp;&nbsp;&nbsp;The name of the volume group to be merged into the <i>TargetVG</i>. This VG will be removed after the merge.<br><br><b>TargetVG</b><br>&nbsp;&nbsp;&nbsp;&nbsp;The name of the volume group that will receive the PVs and LVs from the <i>SourceVG</i>.<br><br><b>-f, --force</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Force the merge operation. Use with extreme caution as it bypasses some safety checks.<br><br><b>--noudevsync</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Do not synchronize with udev. This is typically used in clustered environments to avoid potential conflicts.<br><br><b>--reportformat {basic|json}</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Select the output format for reports generated by <b>LVM</b> commands. While not directly altering the merge, it's a common option for <b>LVM</b> tools.<br><br>


title: DESCRIPTION
content:
<i>vgmerge</i> is a crucial <b>LVM</b> (Logical Volume Manager) command used to consolidate storage by merging two existing volume groups into a single, larger one. When executed, it transfers all physical volumes (PVs) and logical volumes (LVs) from the <i>SourceVG</i> to the <i>TargetVG</i>. After a successful merge, the <i>SourceVG</i> ceases to exist, and its resources become part of the <i>TargetVG</i>.<br><br>This operation is typically performed to simplify storage management, increase the capacity of an existing volume group, or to decommission a smaller, separate volume group while retaining its data. It's a powerful command that permanently alters your <b>LVM</b> setup, so careful planning and backups are highly recommended before execution.


title: CAVEATS
content:
The <i>SourceVG</i> must be inactive and have no open logical volumes.<br>The <i>TargetVG</i> must be active.<br>All physical volumes of the <i>SourceVG</i> must be present and healthy. Missing PVs will prevent the merge.<br>Both volume groups must have compatible <b>LVM</b> metadata.<br>This is a destructive operation for the <i>SourceVG</i>; ensure all data is accounted for or backed up beforehand.


title: PRE-MERGE CHECKS
content:
Before attempting a merge, always verify the status of both volume groups using <i>vgs</i>, <i>lvs</i>, and <i>pvs</i>. Ensure the <i>SourceVG</i> is deactivated (e.g., <i>vgchange -an SourceVG</i>) and that no logical volumes within it are in use or mounted.


title: ROLLBACK CONSIDERATIONS
content:
There is no direct 'unmerge' command. If a problem occurs, restoring from backup or manually recreating the volume groups and data might be necessary. This underscores the importance of thorough planning and backup procedures.


title: HISTORY
content:
<i>vgmerge</i> is an integral part of the <b>LVM</b> (Logical Volume Manager) suite of tools on Linux. <b>LVM</b> was initially developed by Joe Thornber and first released in 1998. It was significantly enhanced with the introduction of <b>LVM2</b>, which provided a more robust and flexible architecture.<br><br><i>vgmerge</i> has been a staple command within the <b>LVM</b> utilities, allowing administrators to dynamically manage and consolidate storage resources, reflecting the ongoing need for flexible storage solutions in evolving IT environments. Its functionality remains critical for maintaining and optimizing complex storage configurations.


title: PARAMETERS
content:
<b><b>-a</b>, <b>--all</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Creates device nodes for all known LVM logical volumes across all volume groups.<br><br><b><b>-c</b>, <b>--chown</b> {<I>User</I>|<I>Group</I>}</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Changes the user or group owner of the created device nodes. For example, <I>root:disk</I>.<br><br><b><b>-g</b>, <b>--chgrp</b> <I>Group</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Changes the group owner of the created device nodes.<br><br><b><b>-m</b>, <b>--chmod</b> <I>Mode</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Sets the permissions mode for the created device nodes (e.g., <I>0600</I> or <I>0660</I>).<br><br><b><b>-f</b>, <b>--force</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces the creation or recreation of nodes, even if they already exist or other conditions might prevent it.<br><br><b><b>-n</b>, <b>--node-format</b> <I>Format</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies a custom format string for naming the device nodes, allowing placeholders like <I>%VG</I> (Volume Group name) and <I>%LV</I> (Logical Volume name).<br><br><b><b>-t</b>, <b>--test</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Runs the command in test mode, displaying what actions would be performed without actually creating or modifying any device nodes.<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Enables verbose debugging output, providing more detailed information about the command's execution.<br><br><b><I>VolumeGroupName</I>...</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies one or more Volume Group names for which to create logical volume device nodes. If omitted and <I>--all</I> is not used, it typically processes active volume groups.<br><br>


title: DESCRIPTION
content:
<b>vgmknodes</b> is a utility within the LVM2 (Logical Volume Manager) suite. Its primary purpose is to ensure that the special block device files (nodes) corresponding to LVM logical volumes (LVs) exist in the <I>/dev</I> directory.<br><br>These device nodes are essential for accessing the logical volumes, allowing them to be mounted, used by applications, or otherwise interacted with like regular block devices. In modern Linux systems, <I>udev</I> (or similar dynamic device management systems) typically handles the automatic creation and management of these device nodes when LVM volumes are activated or detected.<br><br>Therefore, <b>vgmknodes</b> is less frequently needed for day-to-day operations. However, it remains a crucial tool for troubleshooting, recovery scenarios, or in environments where <I>udev</I> might not be fully functional or enabled. It can be used to manually re-create missing device nodes after system reboots, LVM configuration changes, or if the <I>/dev</I> directory has been cleaned. The command can operate on specific volume groups or all detected LVM volumes, ensuring their respective device files are present and have the correct permissions.


title: CAVEATS
content:
<I>Automatic Management</I>: In most modern Linux distributions, <I>udev</I> (or a similar system) automatically creates LVM device nodes when volumes are activated or detected. Manual use of <b>vgmknodes</b> is typically only necessary for troubleshooting, system recovery, or in environments without <I>udev</I>.<br><br><I>Permissions</I>: Incorrect use of <I>--chown</I>, <I>--chgrp</I>, or <I>--chmod</I> can lead to permission issues, preventing proper access to logical volumes.<br><br><I>Major/Minor Numbers</I>: While options for specifying major/minor numbers exist (e.g., <I>-s</I>, <I>-M</I>), they are rarely used directly by administrators as these are handled by the kernel and device management systems.


title: NODE PATHS
content:
LVM device nodes are typically found in <I>/dev/<VolumeGroupName>/<LogicalVolumeName></I>. For example, <I>/dev/myvg/mylv</I>. These are symbolic links pointing to the actual device files in <I>/dev/mapper/</I>.


title: INTERACTION WITH UDEV
content:
When <I>udev</I> is running, <b>vgmknodes</b> is often invoked internally by other LVM commands (like <I>vgchange -a y</I>) or by <I>udev</I> rules themselves, rather than being run as a standalone command by the user. If <I>udev</I> is not running or misconfigured, <b>vgmknodes</b> can be used to manually populate <I>/dev</I>.


title: HISTORY
content:
<b>vgmknodes</b> is an integral part of the LVM2 project, which significantly re-architected LVM from its original LVM1 version. Its importance has shifted over time; in earlier Linux systems or those without robust dynamic device management, manually running <b>vgmknodes</b> after reboots or LVM configuration changes was common. With the widespread adoption and sophistication of <I>udev</I> (and <I>systemd</I> integration), the need for explicit manual execution of <b>vgmknodes</b> has greatly diminished, as <I>udev</I> handles the dynamic creation and removal of LVM device nodes as volumes are activated/deactivated. Despite less frequent direct usage, it remains a vital component of LVM's underlying functionality and a fallback tool for system administrators.


title: PARAMETERS
content:
<b><i>INPUT_FILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The path to the video game audio file to be processed. This is a mandatory argument.<br><br><b><i>OUTPUT_FILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The path where the decoded audio will be saved. If omitted, the command typically outputs to standard output (stdout), which can then be piped to another player (e.g., aplay) or a file. This argument is only used for conversion.<br><br><b><b>-o</b> <i>FILE</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specifies the output file path. Equivalent to providing <i>OUTPUT_FILE</i> directly as the second argument.<br><br><b><b>-p</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Plays the decoded audio directly to the system's default audio device (via aplay or similar backend). No output file is created.<br><br><b><b>-s</b> <i>STREAM_INDEX</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Selects a specific audio stream within a multi-stream input file. Some game formats contain multiple tracks or variations.<br><br><b><b>-l</b> <i>LOOP_COUNT</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Loops the audio track a specified number of times. Use <b>0</b> for infinite looping, <b>1</b> for no looping (play once).<br><br><b><b>-f</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces overwrite of the output file if it already exists, without prompting for confirmation.<br><br><b><b>-m</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Prints detailed metadata about the input file to standard output, including track duration, sample rate, channels, and loop points, without decoding the audio.<br><br><b><b>--tags</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Shows tag information (if available) for the input file, such as title, artist, or album.<br><br><b><b>--loop-silence</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Adds a short period of silence after each loop when looping is enabled, preventing abrupt transitions.<br><br><b><b>--decode-samples</b> <i>NUM_SAMPLES</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Decodes only a specified number of samples from the input file. Useful for debugging or extracting short segments.<br><br><b><b>--raw</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Outputs raw PCM audio data to standard output, without any header. Useful for piping to tools that expect raw audio.<br><br><b><b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a help message with available options and their descriptions.<br><br><b><b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Prints the version information of <i>vgmstream_cli</i>.<br><br>


title: DESCRIPTION
content:
<i>vgmstream_cli</i> is the command-line interface for the <b>vgmstream</b> library, a powerful tool designed to decode and play a vast array of proprietary audio formats commonly found in video games. Unlike standard media players that focus on general-purpose audio/video formats, <i>vgmstream_cli</i> specializes in the often complex and unique sound formats specific to game consoles and PC games. It can be used to play these files directly through an audio output device or, more commonly, to convert them into standard formats like WAV or Ogg Vorbis for broader compatibility and editing. Its primary utility lies in making otherwise inaccessible game music available for listening, archiving, or further processing.


title: CAVEATS
content:
Due to the diverse and often undocumented nature of video game audio formats, <i>vgmstream_cli</i> may not support every existing format, or some formats may have partial support. Compatibility is continuously updated, but users may encounter files that cannot be decoded. Performance can vary depending on the complexity of the format and the system's hardware. Additionally, direct playback (<b>-p</b> option) often relies on external tools like <i>aplay</i>, which must be installed and configured correctly on the system.


title: COMMON USE CASES
content:
<b>Conversion:</b> Converting game music into standard WAV or Ogg Vorbis files for use in other applications or for archival purposes.<br><b>Direct Playback:</b> Quickly listening to a game music track without needing a dedicated player plugin.<br><b>Metadata Extraction:</b> Examining the internal structure and properties of game audio files for research or development.<br><b>Looping Audio:</b> Creating endlessly looping background music for custom projects or streams by utilizing the loop functionality.


title: INSTALLATION
content:
<i>vgmstream_cli</i> is typically available in the package repositories of many Linux distributions (e.g., Debian/Ubuntu: <b>sudo apt install vgmstream</b>, Arch Linux: <b>sudo pacman -S vgmstream</b>). Alternatively, it can be compiled from source by downloading the <b>vgmstream</b> project from its official GitHub repository.


title: HISTORY
content:
The <b>vgmstream</b> project began as a dedicated effort by developers, notably 'hcs', to address the lack of support for proprietary video game audio formats in general-purpose media players. Over time, it evolved into a comprehensive library capable of handling hundreds of obscure and complex formats from various game consoles and PC games. <i>vgmstream_cli</i> emerged as the command-line frontend, providing a versatile interface for users to decode, convert, and play these unique audio files without relying on graphical interfaces or specific game emulators. Its development is ongoing, with new formats and improvements continuously added by a community of contributors.


title: PARAMETERS
content:
<b><b>-a</b>, <b>--all</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<I>Reduce all volume groups by removing any empty physical volumes.</I><br><br><b><b>-f</b>, <b>--force</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<I>Bypass some checks; use with extreme caution as it can lead to data loss.</I><br><br><b><b>-t</b>, <b>--test</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<I>Run in test mode; actions are not actually performed but printed.</I><br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<I>Provide more detailed output.</I><br><br><b><b>--removemissing</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<I>Remove all missing physical volumes from the specified volume group(s).</I><br><br><b><b>--noudevsync</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<I>Disable udev synchronization. Use if udev is not running or causing issues.</I><br><br><b><b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<I>Display the version of LVM2 tools.</I><br><br><b><b>-h</b>, <b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;<I>Display a help message and exit.</I><br><br>


title: DESCRIPTION
content:
<b>vgreduce</b> is a command-line utility used in Logical Volume Management (LVM) to reduce the size of an existing volume group (VG) by removing one or more physical volumes (PVs) from it. This operation allows an administrator to reclaim PVs for other purposes, such as adding them to different volume groups, using them for non-LVM storage, or physically removing them from the system.<br><br>Before a physical volume can be successfully removed from a volume group using <b>vgreduce</b>, all logical volume (LV) extents allocated on that PV must first be moved off. If any logical extents remain on the PV, <b>vgreduce</b> will typically fail, preventing accidental data loss. The <b>pvmove</b> command is commonly used to migrate data from a PV targeted for removal to other PVs within the same volume group. After <b>vgreduce</b> successfully removes a PV, the LVM metadata is updated, and the PV becomes available for new assignments.


title: CAVEATS
content:
It is critical to ensure that no logical volumes (LVs) are allocated on the physical volume(s) being removed from a volume group. If LVs reside on the PV(s), <b>vgreduce</b> will prevent the operation to avoid data loss, unless overridden by <b>--force</b>, which is highly discouraged. Always use <b>pvmove</b> to migrate data off the PV before attempting to remove it. Removing a PV that still contains data will lead to immediate data corruption and potential loss of the affected logical volumes. You cannot reduce a volume group if the specified physical volume is the last remaining PV, unless it is truly empty.


title: HANDLING MISSING PHYSICAL VOLUMES
content:
<I>In scenarios where a physical volume has become permanently unavailable (e.g., disk failure, accidental removal) and its data is no longer accessible, <b>vgreduce</b> can be used with the <b>--removemissing</b> option. This option tells LVM to remove references to the missing PVs from the volume group's metadata. This action should only be performed if you are certain the PV is irretrievably lost and any data on it is already accounted for or not needed, as it will likely mark associated logical volumes as invalid or corrupted if they used extents on the missing PV. Before using this, it's crucial to understand the implications for data integrity.</I>


title: HISTORY
content:
The <b>vgreduce</b> command is an integral part of the Logical Volume Manager (LVM2), which is the standard LVM implementation for Linux systems. LVM itself was initially inspired by proprietary UNIX LVM implementations like those found in HP-UX. LVM2, released in the early 2000s, brought significant improvements over its predecessor (LVM1), including better scalability, robustness, and a more unified command set. <b>vgreduce</b> has been a stable and essential component of LVM2 since its inception, providing administrators with the flexibility to manage and optimize storage resources dynamically by safely shrinking volume groups as needed. Its functionality is fundamental to maintaining efficient and adaptable disk configurations in modern Linux environments.


title: SEE ALSO
content:
<i>pvmove(8)</i>, <i>vgcreate(8)</i>, <i>vgextend(8)</i>, <i>vgdisplay(8)</i>, <i>pvdisplay(8)</i>, <i>lvm(8)</i>


title: PARAMETERS
content:
<b><b>-f</b>, <b>--force</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Forces the removal of a volume group, even if it contains inactive logical volumes. <i>Use with extreme caution, as this can lead to data loss.</i><br><br><b><b>-y</b>, <b>--yes</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Assumes "yes" to all questions; do not prompt for confirmation.<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays verbose runtime information, showing more details about the command's execution.<br><br><b><b>--autobackup {y|n}</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Controls if metadata is automatically backed up after the command executes. Default is 'y'.<br><br><b><b>--config <i>report.output_format={native|json}</i></b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Configures the output format for reports. Not typically used with <i>vgremove</i> directly for its primary function.<br><br><b><b>--ignorelockingfailure</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Continues with the operation even if a lock cannot be acquired or if a locking file is corrupt.<br><br><b><b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays the version of LVM utilities.<br><br><b><b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Displays a help message and exits.<br><br>


title: DESCRIPTION
content:
<i>vgremove</i> is a fundamental command within the Logical Volume Manager (LVM) framework in Linux, designed to delete one or more existing volume groups. A volume group (VG) is the highest-level abstraction in LVM, comprising one or more physical volumes (PVs) and acting as a container for logical volumes (LVs).<br><br>Before a volume group can be removed, all logical volumes residing within it must be removed first using the <i>lvremove</i> command. Removing a volume group permanently discards all LVM metadata associated with it and its constituent physical volumes, making the underlying disk space available for other uses. This operation is irreversible and will lead to data loss if logical volumes were not properly removed beforehand. It's crucial to ensure that no logical volumes are active or mounted before attempting to remove their parent volume group. <i>vgremove</i> helps in tidying up disk space, reconfiguring storage, or preparing disks for re-purposing.


title: CAVEATS
content:
<ul><li><b>Data Loss</b>: Removing a volume group is a destructive operation. If any logical volumes within the VG are not removed using <i>lvremove</i> first, their data will be lost irrevocably upon <i>vgremove</i> execution.</li><li><b>Prerequisites</b>: All logical volumes within the volume group must be unmounted and removed before the volume group itself can be removed. Active or mounted LVs prevent VG removal unless forced.</li><li><b>Metadata</b>: <i>vgremove</i> removes the LVM metadata associated with the volume group and its physical volumes. This metadata is essential for LVM to recognize and manage the storage.</li><li><b>Force Option</b>: The <b>-f</b> (force) option should be used with extreme caution as it bypasses checks and can lead to immediate data loss if logical volumes are still present, even if inactive.</li></ul>


title: METADATA BACKUP
content:
Before performing any <i>vgremove</i> operation, it is highly recommended to manually back up your LVM metadata using <i>vgcfgbackup</i>. This can be crucial for disaster recovery in case of accidental removal or other issues.


title: UNMOUNTING LVS
content:
Always ensure that all logical volumes residing within the volume group are unmounted (<i>umount</i>) before attempting to remove them with <i>lvremove</i>. This prevents data corruption and ensures a clean removal process.


title: HISTORY
content:
<i>vgremove</i> is a core component of the Logical Volume Manager (LVM) suite, which has been an integral part of Linux since its introduction in the early 2000s, building upon similar concepts from commercial Unix systems. LVM provides a flexible way to manage disk space, abstracting physical storage into logical units. The <i>vgremove</i> command has been present since the early versions of LVM, evolving alongside the LVM framework itself, primarily in terms of robustness, error handling, and support for new LVM features, rather than fundamental changes to its core function of deleting volume groups. Its consistent purpose reflects its foundational role in LVM's storage management capabilities.


title: SYNOPSIS
content:
<b>vgrename</b> [<i>OPTIONS</i>] <i>OldVG NewVG</i><br><b>vgrename</b> [<i>OPTIONS</i>] <i>UUID NewVG</i>


title: PARAMETERS
content:
<b><i>OldVG</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The current name of the volume group to be renamed.<br><br><b><i>NewVG</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The desired new name for the volume group.<br><br><b><i>UUID</i></b><br>&nbsp;&nbsp;&nbsp;&nbsp;The UUID of the volume group to be renamed. Useful if there are name conflicts or the old name is unknown.<br><br><b><b>-y</b>, <b>--yes</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Answer yes to all questions, bypassing interactive prompts.<br><br><b><b>-f</b>, <b>--force</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Force the rename operation. Use with caution.<br><br><b><b>--noudevsync</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Disable udev synchronization. Useful in specific environments, but generally not recommended for normal operation.<br><br><b><b>-t</b>, <b>--test</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Run in test mode. Do not actually perform any changes, but show what would happen.<br><br><b><b>-v</b>, <b>--verbose</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Provide verbose output, showing more details about the operation.<br><br><b><b>-q</b>, <b>--quiet</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppress output messages, only showing errors.<br><br><b><b>-h</b>, <b>--help</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display a help message and exit.<br><br><b><b>--version</b></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display the version information and exit.<br><br>


title: DESCRIPTION
content:
The <b>vgrename</b> command is used to change the name of an existing LVM (Logical Volume Manager) volume group. This operation is crucial when you need to standardize naming conventions, resolve naming conflicts, or simply improve the organization of your storage infrastructure. Before renaming, it's generally required to deactivate the volume group and all its contained logical volumes to ensure data integrity and prevent issues during the rename process. Once renamed, any references to the old volume group name, such as those in `/etc/fstab` or other configuration files, must be manually updated to reflect the new name. It's a fundamental LVM utility for managing the logical structure of disk storage.


title: CAVEATS
content:
Before renaming, the volume group and all its logical volumes must be <i>deactivated</i> using <b>vgchange -an <i>OldVG</i></b>. Failure to do so can lead to errors or data corruption. After a successful rename, remember to update all configuration files (e.g., <i>/etc/fstab</i>, bootloader configurations like GRUB) that refer to the old volume group name. If the system uses a clustered LVM setup, special considerations and procedures might be required.


title: PREREQUISITES FOR RENAMING
content:
To successfully rename a volume group, ensure that no logical volumes within it are currently in use or mounted. This often involves unmounting file systems, stopping services, and deactivating the volume group with <b>vgchange -an <i>OldVG</i></b> before executing <b>vgrename</b>. Once renamed, reactivate it with <b>vgchange -ay <i>NewVG</i></b>.


title: UPDATING SYSTEM CONFIGURATION
content:
After renaming a volume group, it is critical to update any system configuration files that reference the old volume group name. This commonly includes <i>/etc/fstab</i> for mounted filesystems, and potentially bootloader configuration files if your root filesystem resides on an LVM logical volume.


title: HISTORY
content:
<b>vgrename</b> is an integral part of the Logical Volume Manager (LVM) suite, which has been a cornerstone of flexible storage management on Linux systems for many years. Its development is tied to the evolution of LVM itself, providing administrators with tools to dynamically manage disk space, allowing for operations like renaming, resizing, and migrating storage components without downtime (for active components, though renaming a VG typically requires deactivation). It has been a standard utility since the early days of LVM2, providing consistent functionality across various Linux distributions.


title: SYNOPSIS
content:
<b>vgrep</b> [<i>options</i>] <i>pattern</i> [<i>file ...</i>]<br>or<br><i>command</i> | <b>vgrep</b> [<i>options</i>] <i>pattern</i>


title: PARAMETERS
content:
<b>-A <I>NUM</I>, --after-context=<I>NUM</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Print <I>NUM</I> lines of trailing context after matching lines.<br><br><b>-B <I>NUM</I>, --before-context=<I>NUM</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Print <I>NUM</I> lines of leading context before matching lines.<br><br><b>-C <I>NUM</I>, --context=<I>NUM</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Print <I>NUM</I> lines of context around matching lines. Equivalent to <b>-A</b> <I>NUM</I> <b>-B</b> <I>NUM</I>.<br><br><b>-v, --invert-match</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Invert the match; select non-matching lines.<br><br><b>-i, --ignore-case</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Ignore case distinctions in patterns and data.<br><br><b>-F, --fixed-strings</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Interpret <I>PATTERN</I> as a list of fixed strings, separated by newlines, any of which is to be matched.<br><br><b>-E, --extended-regexp</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Interpret <I>PATTERN</I> as an extended regular expression (ERE). This is the default.<br><br><b>-G, --basic-regexp</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Interpret <I>PATTERN</I> as a basic regular expression (BRE).<br><br><b>-P, --perl-regexp</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Interpret <I>PATTERN</I> as a Perl regular expression (PCRE).<br><br><b>-w, --word-regexp</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Select only those lines containing matches that form whole words.<br><br><b>-x, --line-regexp</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Select only those matches that match the whole line.<br><br><b>-n, --line-number</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Prefix each line of output with the 1-based line number within its input file.<br><br><b>-h, --no-filename</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppress the prefixing of filenames on output when multiple files are matched.<br><br><b>-H, --with-filename</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Print the filename for each match. This is the default when there is more than one file.<br><br><b>-l, --files-with-matches</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppress normal output; instead print the name of each input file from which output would normally have been printed.<br><br><b>-L, --files-without-matches</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppress normal output; instead print the name of each input file from which no output would normally have been printed.<br><br><b>--exclude=<I>GLOB</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Skip files whose base name matches <I>GLOB</I> (wildcard).<br><br><b>--exclude-dir=<I>GLOB</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Exclude directories whose names match <I>GLOB</I>.<br><br><b>--include=<I>GLOB</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Only search files whose base name matches <I>GLOB</I>.<br><br><b>-m <I>NUM</I>, --max-count=<I>NUM</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Stop reading a file after <I>NUM</I> matching lines.<br><br><b>-s, --no-messages</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Suppress error messages about non-existent or unreadable files.<br><br><b>--color[=<I>WHEN</I>]</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Highlight matches. <I>WHEN</I> can be <I>always</I>, <I>never</I>, or <I>auto</I>.<br><br><b>--group-separator=<I>SEP</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify a string to be printed between groups of matched lines; useful with context options.<br><br><b>--label=<I>LABEL</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Specify the label to display for standard input.<br><br><b>--less-options=<I>OPTS</I></b><br>&nbsp;&nbsp;&nbsp;&nbsp;Pass additional options directly to <i>less</i>.<br><br><b>-V, --version</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display version information and exit.<br><br><b>--help</b><br>&nbsp;&nbsp;&nbsp;&nbsp;Display a help message and exit.<br><br>


title: DESCRIPTION
content:
<i>vgrep</i> is a powerful command-line utility that merges the pattern-matching capabilities of <i>grep</i> with the interactive file browsing features of <i>less</i>. Unlike <i>grep</i> which outputs results and exits, <i>vgrep</i> allows users to search for patterns within files or piped input, then interactively navigate through the matched lines and their surrounding context within a <i>less</i>-like interface. This makes it exceptionally useful for exploring large log files or codebases where you need to quickly locate specific information and then examine the surrounding lines without re-running <i>grep</i> and <i>less</i> separately. It highlights matches and provides common <i>less</i> navigation shortcuts, significantly streamlining the workflow for log analysis and code inspection by offering an immediate interactive view of search results.


title: CAVEATS
content:
<i>vgrep</i> might not be installed by default on all Linux distributions; it's typically part of the <i>moreutils</i> package.<br>While it mimics <i>grep</i>'s options, not all obscure <i>grep</i> options might be fully supported or behave identically.<br>Performance on extremely large datasets (many terabytes) or an enormous number of files might not be as optimized as tools like <i>ripgrep</i> or <i>ag</i> which are designed for raw speed. Its strength is interactivity rather than raw throughput for batch processing.


title: INTERACTIVE NAVIGATION
content:
Once <i>vgrep</i> displays its output, users can navigate the results using standard <i>less</i> commands (e.g., <b>j</b> for next line, <b>k</b> for previous, <b>G</b> for end, <b>g</b> for beginning, <b>/</b> for search within results, <b>n</b> for next match, <b>N</b> for previous match, <b>q</b> to quit). This interactive mode is its primary advantage over traditional <i>grep</i>.


title: COMMON USE CASES
content:
<i>vgrep</i> is ideal for debugging by sifting through large log files, exploring codebases to understand specific function calls or variable usages, and interactively filtering output from other commands where immediate, contextual viewing of results is beneficial.


title: HISTORY
content:
<i>vgrep</i> is part of the <i>moreutils</i> package, a collection of small, useful Unix utilities. <i>moreutils</i> was primarily created and maintained by Wayne Marshall. The utilities in <i>moreutils</i>, including <i>vgrep</i>, aim to extend the standard set of Unix tools by providing small, single-purpose programs that complement existing functionality, often by combining the capabilities of two or more standard tools (like <i>grep</i> and <i>less</i> in <i>vgrep</i>'s case) or providing missing conveniences. Its development philosophy aligns with the Unix tradition of small, composable tools.


