SHELL

keyboard backlight not working linux

#!/bin/bash
# Adjust the keyboard backlight level

shopt -s -o nounset

declare -i KBD_BACKLIGHT_MAX=`cat /sys/class/leds/asus::kbd_backlight/max_brightness`
declare -i KBD_BACKLIGHT_LEV=`cat /sys/class/leds/asus::kbd_backlight/brightness` 

# We need a parameter, etiher inc or dec
if [ $# -eq 0 ] ; then
   exit 192
fi 

case $1 in
-inc ) 
   # increasing:
   if [ ${KBD_BACKLIGHT_LEV} -lt ${KBD_BACKLIGHT_MAX}  ] ; then
      KBD_BACKLIGHT_LEV=${KBD_BACKLIGHT_LEV}+1
      echo ${KBD_BACKLIGHT_LEV} | tee /sys/class/leds/asus::kbd_backlight/brightness
   fi
   ;;
-dec )
   # decreasing:
   if [ ${KBD_BACKLIGHT_LEV} -gt 0 ] ; then
      KBD_BACKLIGHT_LEV=${KBD_BACKLIGHT_LEV}-1
      echo ${KBD_BACKLIGHT_LEV} | tee /sys/class/leds/asus::kbd_backlight/brightness
   fi
   ;;
esac

exit 192