Linux command to list all available commands and aliases

In Linux, there are several methods to view all available commands and their aliases:

1. Using the compgen command

The compgen command is a built-in command of bash that can display all available commands, aliases, keywords, etc. To list all available commands and aliases, you can use the following commands:

bash
compgen -c  # List all available commands
compgen -a  # List all aliases

2. Viewing commands in the PATH environment variable

In Linux, executable files are commonly located in directories specified by the PATH environment variable. You can inspect these directories to find all available commands:

bash
echo $PATH  # Display the PATH environment variable
ls $(echo $PATH | tr ':' ' ')  # List contents of all directories in PATH

3. Using the alias command

To view all aliases defined in the current shell session, you can use:

bash
alias  # List all aliases

4. Using the type command

If you want to check if a specific command exists and determine whether it is an alias, function, keyword, or file, you can use the type command:

bash
type ls  # Check the type of the 'ls' command
type cd

Example

For instance, to search for all commands and aliases containing the keyword 'net' in daily work, you can use the following combined commands:

bash
compgen -c | grep net  # Find commands containing 'net'
compgen -a | grep net  # Find aliases containing 'net'

These commands help you quickly identify network-related tools and aliases, enhancing your work efficiency. In summary, Linux offers multiple tools and commands to assist users in finding and managing system commands and aliases, which are highly beneficial for system administration and daily operations.