Brightness buttons handling via acpid

# cat /etc/acpi/actions/brightness.sh

#! /bin/bash

case $1 in
        -|+) ;;
        *) exit 1;;
esac

dev=/sys/class/backlight/intel_backlight
max=$(< $dev/max_brightness)
cur=$(< $dev/brightness)
step=$(( max / 50 ))

test $((cur * 100 / max)) -lt 21 && step=$(( max / 200 ))

brightness=$((cur $1 step))

test "$brightness" -lt 0 && brightness=0
test "$brightness" -gt "$max" && brightness="$max"

echo "$brightness" > $dev/brightness

# cat /etc/acpi/events/brightness_down

event=video.brightnessdown
action=/etc/acpi/actions/brightness.sh -

# cat /etc/acpi/events/brightness_up

event=video.brightnessup
action=/etc/acpi/actions/brightness.sh +












// (c) Artem S. Tashkinov Jul 23 2016 10:03 GMT