prec7530 brightness control

gravedigger@precision:~$ cat ~/bin/bright
~/bin/brightness.sh up
gravedigger@precision:~$ cat ~/bin/brightness.sh
#!/bin/bash
DEVICE=/sys/class/backlight/intel_backlight/brightness

function get() {
    cat $DEVICE;
}

function set() {
    echo $1 |sudo tee $DEVICE
}
case $1 in
    up)
    temp=`get`;
    temp=$(($temp + 2500));
    set $temp;;
    down)
    temp=`get`;
    temp=$(($temp - 2500));
    set $temp;;
    *)
esac