reboot-when-no-user-logged-in

#!/bin/bash

# This script will issue a reboot command when all interactive users have left the system.
# It's useful for activating a new kernel without bothering the users.
# Changelog:
# 2013-11-14 - Onno - Created

if [ "$1" = "--nohup" ] ; then
  # This script has called itself in a nohup shell. Let's get to work.
  while true ; do
    if [ -z "`who`" ] ; then
      echo "`date` - No user found. Rebooting."
      reboot
    else
      echo "`date` - Users found. Sleeping."
    fi
    sleep 60
  done
else
  echo "This script will call itself in a nohup shell. You can log out. If all users have left the system, it will be rebooted. To cancel the reboot, do 'ps -ef | grep nohup' and kill this script."
  nohup $0 --nohup &
fi