The command userdel -r johndoe will remove the user 'johndoe' and delete the user's home directory as well as the mail spool. The -r option stands for 'remove' and is used specifically for this purpose. Simply using userdel johndoe would not remove the home directory or mail spool. deluser and removeuser are not standard Linux commands. It is essential to use the correct options and command to ensure proper cleanup of user accounts.