Hi Shwick!

I'm not exactly sure what you're trying to do with the usermod command there. If it's giving you the usage, then you've likely got a syntax error somewhere. What's the end result you've got in mind here?

On the sudo issue, the "sudo" password is always going to be the password of the user that's running ths sudo command. That's what "sudo" does, it gives a user the ability to run specific commands (or all of them) as a privileged user, using their own login credentials.

If you don't want a user to have sudo access, remove them from the sudoers group. I'm assuming we're talking about Ubuntu here, in which case it's probably the "admin" group. You should be able to tell by checking out the /etc/sudoers file.

Hope this helps!
-G