How to Find Commands/Aliases In Bash

The aim of this page📝 is to explain how to print and filter available commands in Bash.

compgen is a built-in Bash command that generates possible completion matches for a given string. It’s a powerful tool for listing commands, aliases, built-ins, keywords, and functions available in your shell. You can think of using compgen in Bash as a similar approach to using Get-Command and Get-Alias in PowerShell. Both sets of commands are used to list and discover available commands and aliases in their respective shells.

• Use compgen to list all available commands in Bash.
• compgen -c lists all commands.
• compgen -a lists all aliases.
• compgen -b lists all built-ins.
• compgen -k lists all keywords.
• compgen -A function lists all functions.
• Combine these options to list everything: compgen -c -a -b -k -A function.
• Pipe the output through sort and uniq to sort and remove duplicates.
• Use grep -E "$regex" to filter commands based on a regex pattern.
• Create a function to encapsulate this logic.
• Example function named cmd from my .bash_profile
• I use ripgrep (rg) instead of grep …

function cmd() {
  regex="$1"
  compgen -c -a -b -k -A function | sort | uniq | rg "$regex"
}

bash command discovery in action

• Call the function with a regex pattern to find matching commands.
• Example usage: cmd "my_custom" to find commands matching “my_custom”.