brightness

#!/bin/bash
#file that stores the brightness
bgFile="/sys/class/backlight/acpi_video0/brightness"

currentValue=$(cat "$bgFile")
if [ -z $1 ]; then
	echo $currentValue
elif [ $1 == "set" ]; then
	echo $2 > $bgFile
elif [ $1 == "inc" ]; then
	echo $(($currentValue+$2)) > $bgFile
elif [ $1 == "dec" ]; then
	echo $(($currentValue-$2)) > $bgFile
else
	printf "run command without any paraments to get current brightness value.\nuse 'set <int>' to set the brightness.\nuse 'inc <int>' to increase the brightness with the given value.\nuse 'dec <int>' to decrease the brightness with the given value."

fi