brightness

#!/bin/bash

if [ $(whoami) != "root" ]; then
    sudo $0 $*
    exit 0
fi

case $(hostname) in
    daniel-laptop)
        DEVICE=acpi_video0
        ;;
    daniel-eee)
        DEVICE=psblvds
        ;;
    *)
        echo "Unknown host"
        exit 1
        ;;
esac

CUR=$(cat /sys/class/backlight/$DEVICE/brightness)
MAX=$(cat /sys/class/backlight/$DEVICE/max_brightness)
STEP=$(echo $MAX/10 | bc)

function set_brightness() {
    if [ "$1" -gt "$MAX" ]; then
        new=$MAX
    else
        if [ "$1" -lt "0" ]; then
            new=0
        else
            new=$1
        fi
    fi

    echo $new > /sys/class/backlight/$DEVICE/brightness
}

case "$1" in
    up)
        set_brightness $(echo "$CUR+$STEP" | bc)
        ;;
    down)
        set_brightness $(echo "$CUR-$STEP" | bc)
        ;;
    max)
        set_brightness $MAX
        ;;
    min)
        set_brightness 0
        ;;
    [0-9]*)
        set_brightness $1
        ;;
    "")
        echo $CUR
        ;;
    *)
        echo "usage: $0 [up|down|max|min|0-9*]"
        exit 1
esac