If you're using bash or zsh and you don't know the ^X^E shortcut, learn it now.
First, ensure you have a valid `EDITOR` environment variable set to your favourite editor (like vim or emacs).
Second, enter some command, but don't hit enter.
Third, use Ctrl+X Ctrl+E and learn that you can use your editor to modify the command before running it in the shell.
This is pretty helpful if you're trying to edit a long command line.