Script to fix backlight issue (dark screen) for HP g62 laptop on Ubuntu 11.10

backlight.sh

#!/bin/bash

# Fix the backlight issue on Ubuntu 11.10 for
# a HP G62 laptop. Add this script to the startup
# applications. In addition, make sure to make
# /sys/class/backlight/intel_backlight
# world-writable (chmod 777), for example
# in /etc/rc.local
#
# Examples:
#
# Set backlight to max:
# ./backlight 
#
# Sleep for 10 seconds before setting backlight
# to max:
# ./backlight sleep 10
#
# Turn up backlight:
# ./backlight up
#
# Turn down backlight:
# ./backlight down

LOC=/sys/class/backlight/intel_backlight
if [ $# == 0 ]; then
	echo 'MAX'
	cat $LOC/max_brightness > $LOC/brightness
elif [ $1 == 'sleep' ]; then
	sleep $2
	echo 'MAX'
	cat $LOC/max_brightness > $LOC/brightness
elif [ $1 == 'up' ]; then
	echo $[ `cat $LOC/brightness` + 256 ] > $LOC/brightness 
	echo 'UP'
elif [ $1 == 'down' ]; then
	echo $[ `cat $LOC/brightness` - 256 ] > $LOC/brightness
	echo 'DOWN'
fi