Added the -G option to allow logins only for users that are members of a certain group. This allows finer control of an instance on who can and cannot login over a certain instance (e.g. password and not key). Needs double-checking and ensuring it meets platform requirements.

#!/bin/bash
if cvs log $1 >/dev/null 2>/dev/null; then exit 0; else echo "$1 shouldn't be here, removed"; rm -f $1 ; fi