MacBook Pro keyboard backlight keys on Ubuntu GNU/Linux

Inked by Fran Dieguez
Recently I have purchased a new MacBook Pro 15" and the first thing I do was install [Ubuntu Lucid Lynx](https://wiki.ubuntu.com/LucidLynx) on it.

After some readying I have all the hardware working properly but the keyboard backlight wasn’t integrated into system and unfortunately after searching on the web for something that could do this, I decide to write a simple script with Bash and use Ubuntu-tweak to bind the keyboard keys to invoke the script. So let’s go…

Preparing our system

Well, before try to install my script on your computer you must have installed the applesmc module on your computer. Don’t worry, if you go to help.ubuntu.com you’ll find specific instructions to install it.

Installing my script at your system

Just right-click on this link, save to your computer and rename it to keyboard-backlight. You can drop it at /usr/bin to execute from wherever you are. Here are the contents of the script If you are curious:

BACKLIGHT=$(cat /sys/class/leds/smc::kbd_backlight/brightness)
INCREMENT=15

if [ $UID -ne 0 ]; then
    echo "Please run this program as superuser"
    exit 1
fi

SET_VALUE=0
case $1 in

    up)
        TOTAL=`expr $BACKLIGHT + $INCREMENT`
        if [ $TOTAL -gt "255" ]; then
            exit 1
        fi
        SET_VALUE=1
        ;;
    down)
        TOTAL=`expr $BACKLIGHT - $INCREMENT`
        if [ $TOTAL -lt "0" ]; then
            exit 1
        fi
        SET_VALUE=1
        ;;
    total)
    TEMP_VALUE=$BACKLIGHT
    while [ $TEMP_VALUE -lt "255" ]; do
        TEMP_VALUE=`expr $TEMP_VALUE + 1`
        if [ $TEMP_VALUE -gt "255" ]; then TEMP_VALUE=255; fi
        echo $TEMP_VALUE > /sys/class/leds/smc::kbd_backlight/brightness
    done
        ;;
    off)
    TEMP_VALUE=$BACKLIGHT
    while [ $TEMP_VALUE -gt "0" ]; do
        TEMP_VALUE=`expr $TEMP_VALUE - 1`
        if [ $TEMP_VALUE -lt "0" ]; then TEMP_VALUE=0; fi
        echo $TEMP_VALUE > /sys/class/leds/smc::kbd_backlight/brightness
    done
        ;;
    *)
        echo "Use: keyboard-light up|down|total|off"
        ;;
esac

if [ $SET_VALUE -eq "1" ]; then
    echo $TOTAL > /sys/class/leds/smc::kbd_backlight/brightness
fi

Using keyboard-backlight from command-line

This script could have 4 different uses:

  • Increase backlight keyboard: sudo keyboard-backlight up
  • Decrease backlight keyboard: sudo keyboard-backlight down
  • Increase to total value of keyboard backlight: sudo keyboard-backlight total
  • Turn off backlight keyboard: sudo keyboard-backlight off

You can customize the amount of steps by changing the INCREMENT variable inside keyboard-backlight file.