GCE auto shutdown

autoshutdown.sh

#!/bin/sh

do_shutdown () {
  wall "Auto shutdown!"
  sync
  # Replace next line to your shut down command
  gcloud compute instances stop instance-N --zone\=us-central1-a && shutdown -h now
}

warning () {
  wall "Auto shutdown will start after $1 min.
To cancel, 
sudo killall autoshutdown.sh"
}

if [ $# -ge 1 ]; then
  tx=$1
  if [ $tx -le 60 ]; then
    tx=60
  fi
else 
  case `nproc` in
    "1") tx=$((60*8));;
    "2") tx=$((60*6));;
    "3") tx=$((60*5));;
    "4") tx=$((60*4));;
    *) tx=$((60*3));;
  esac
fi

(
  sleep $(($tx - 60))m
  tx=$(($tx - 60))
  warning 60
  sleep 45m
  warning 15
  sleep 10m
  warning 5
  sleep 5m
  do_shutdown
  sleep 5m
  do_shutdown
)&