Logout user after 10 minutes

#!/usr/bin/bash
###
### Use this script to limit account usage
###
notify-send 'Session Timeout' 'Starting timer 15 minutes...' -u critical -t 10000 -i dialog-info
sleep 15m
playsound /home/mruckman/Scripts/ding.wav
notify-send 'Session Timeout' 'One minute before automatic log out. Save your work.' -u critical -t 60000 -i messagebox_critical
sleep 1m
### FORCE LOGOFF
gnome-session-save --force-logout --silent
### LOCK SCREEN, DOES NOT WORK IN ALL CASES
### gnome-screensaver-command --lock