Ubuntu and other distributions give suggestions on the command line if you misspell commands or use commands that are not installed yet. This can be quite helpful in some cases, but if you are like me, you don’t want eight lines of command suggestions just because you mistyped grep as gre. You can disable command suggestions by uninstalling two packages:

$sudo dpkg -r command-not-found
$sudo dpkg -r command-not-found-data

Once you do this and logout and login from the terminal, you’ll be back to the usual unhelpful-but-terse error message.