#!/bin/sh

max_brightness=`cat /sys/class/backlight/intel_backlight/max_brightness`
brightness=`cat /sys/class/backlight/intel_backlight/brightness`
increment=12000

if [ "$1" = "down" ]; then
    new_brightness=$(($brightness - $increment))
    if [ $new_brightness -lt 0 ]; then
        new_brightness=0
    fi
else
    new_brightness=$(($brightness + $increment))
    if [ $new_brightness -gt $max_brightness ]; then
        new_brightness=$max_brightness
    fi
fi

echo $new_brightness > /sys/class/backlight/intel_backlight/brightness
ratio=$(( (new_brightness * 100) / max_brightness ))
notify-send -r 43 "Brightness: ${ratio}%"