compgen

A built-in command for auto-completion in Bash, which is called on pressing TAB key twice. More information: https://www.gnu.org/software/bash/manual/bash.html#index-compgen.

• List all commands that you could run:
  compgen -c
• List all aliases:
  compgen -a
• List all functions that you could run:
  compgen -A function
• Show shell reserved keywords:
  compgen -k
• See all available commands/aliases starting with 'ls':
  compgen -ac {{ls}}