How to use the command `virsh-help` (with examples)

The virsh-help command is used to display information about different commands and command groups in the virsh tool, which is used for managing virtual machines in the KVM (Kernel-based Virtual Machine) hypervisor. This command provides a helpful resource for understanding the available commands and how to use them.

Use case 1: List the virsh commands grouped into related categories

Code:

virsh help

Motivation: The virsh help command is useful when you want to get a comprehensive list of commands available in the virsh tool. This can be helpful for beginners who are learning how to use virsh and want to explore the available commands.

Explanation: This command lists all the available virsh commands grouped into related categories. It provides a high-level overview of the different functionalities offered by virsh for managing virtual machines.

Example output:

Command group 'domain':
  * attach-device
  * attach-disk
  * attach-interface
  * autostart
  ...
Command group 'interface':
  * create
  * define
  ...

Use case 2: List the command categories

Code:

virsh help | grep "keyword"

Motivation: The virsh help | grep "keyword" command is helpful when you want to find specific command categories related to a keyword. This can be useful when you want to quickly filter out commands that are not relevant to your current task.

Explanation: The command virsh help lists all the available command categories, and the grep command is used to filter the output based on a keyword specified within the double-quotes. This allows for a more targeted search for specific command categories.

Example output:

Command group 'domain':
Command group 'interface':

Use case 3: List the commands in a category

Code:

virsh help category_keyword

Motivation: The virsh help category_keyword command is useful when you want to list all the commands within a specific category. This can be helpful for exploring the available commands within a certain functionality.

Explanation: In this command, you need to replace category_keyword with the desired command category keyword. This will list all the commands within that category, providing an overview of the available functionalities.

Example output:

Command group 'interface':
  * create
  * define
  ...

Use case 4: Show help for a command

Code:

virsh help command

Motivation: The virsh help command command is helpful when you want to get detailed information about a specific command. This can be useful when you need more information about how to use a particular command or understand its options and arguments.

Explanation: In this command, you need to replace command with the specific command for which you want to see the help. This will provide a detailed explanation of the command, including its options, arguments, and usage examples.

Example output:

Command: define
Description: define a domain from an XML file
Usage: define <filename>
...

Conclusion:

The virsh-help command is a versatile tool for understanding and exploring the available commands in the virsh tool. With its ability to list commands by category and provide help for specific commands, it becomes an essential resource for users managing virtual machines using KVM.