script to turn off and on Raspberry Pi Display by detecting IP or bluetooth device

screensaver.sh

#!/bin/bash

while true
do
  if ping -c 1 -w 3 192.168.2.67 &> /dev/null || hcitool scan | grep -q -E "ming-macbook|Ming's iPhone" ; then
    echo "welcome back. turning screen on"
    echo 0 | sudo tee /sys/class/backlight/rpi_backlight/bl_power
  else
    echo "you're gone. turning screen off"
    echo 1 | sudo tee /sys/class/backlight/rpi_backlight/bl_power
  fi

  sleep 10
done