Deleting a User and Removing a User From a Group

If you want to remove a user from a group you can use the following command:

      sudo deluser <username> <groupname>

So to remove user 'newuser' from the group 'adm' you would type:

      sudo deluser newuser adm

A similar command can be used to delete an entire user along with it's home directory:

      sudo deluser <username>