Shell script to modify the ASUS Keyboard LED backlight Brightness

asus_kb_backlight.sh

#!/bin/bash

# Shell script to modify the ASUS Keyboard LED backlight Brightness
# Must be run as root

# This script is licensed CC0 by Andrew Harvey <andrew.harvey4@gmail.com>
#
# To the extent possible under law, the person who associated CC0
# with this work has waived all copyright and related or neighboring
# rights to this work.
# http://creativecommons.org/publicdomain/zero/1.0/

if [ "$1" == "" ] ; then
    echo "Usage: $0 (up|down|min|max|off|on|0..n)"
    exit
fi

function kb_backlight {
    echo $1 > /sys/devices/platform/asus-nb-wmi/leds/asus\:\:kbd_backlight/brightness
}

kb=`cat /sys/devices/platform/asus-nb-wmi/leds/asus\:\:kbd_backlight/brightness`
max_kb=`cat /sys/devices/platform/asus-nb-wmi/leds/asus\:\:kbd_backlight/max_brightness`

if [ "$1" == "up" ] ; then
    if [ $kb -lt $max_kb ] ; then
        kb_backlight $(($kb + 1))
    fi
elif [ "$1" == "down" ] ; then
    if [ $kb -gt 0 ] ; then
        kb_backlight $(($kb - 1))
    fi
elif [ "$1" == "min" ] ; then
    kb_backlight 0
elif [ "$1" == "off" ] ; then
    kb_backlight 0
elif [ "$1" == "max" ] ; then
    kb_backlight $max_kb
elif [ "$1" == "on" ] ; then
    kb_backlight $max_kb
elif [[ ( "$1" -ge 0 ) && ( "$1" -le $max_kb ) ]] ; then
    kb_backlight $1
fi