How can I restrict users of computers to 2 hours only?
This Bash script will lock screen after an interval you specify and require the password to reactivate it.
It gives a count down notification bubble and soft sound at 2 hours, 1 hour, 45, 30, 15, 10, 5, 3, 2 and 1 minute remaining.
As I wrote the script I'd be happy to modify it for anyone. Because it's written in Bash millions of other people with beginner scripting skills can change it as well.