#!/bin/bash

# Need brightness-udev for non root users to access file


function inc_brightness() {
    inc=$1
    current=$(cat /sys/class/backlight/intel_backlight/brightness)
    echo $((current + inc)) > /sys/class/backlight/intel_backlight/brightness
    exit
}

function dec_brightness() {
    dec=$1
    current=$(cat /sys/class/backlight/intel_backlight/brightness)
    echo $((current - dec)) > /sys/class/backlight/intel_backlight/brightness
    exit
}


function main ()
{
    while [[ $# -ne 0 ]]; do
        arg="$1"; shift
        case "$arg" in
            --inc) val=$1; inc_brightness $val ;;
            --dec) val=$1; dec_brightness $val ;;
            * ) [[ $arg =~ \-+.* ]] && echo "$arg unknown"
        esac
    done
}

main "$@"