#!/bin/sh

# brightness adjustment script: /etc/brightness/brightness.sh
# originally for the MSI X340, but should probably work on most laptops

# jwc - http://jwcxz.com

bmax=8	# or =`cat /sys/class/backlight/acpi_video0/max_brightness`
bmin=0

bound () {
	if [ "$1" -gt $bmax ]; then return $bmax; fi
	if [ "$1" -lt $bmin ]; then return $bmin; fi
	return $1
}

bset () {
	echo $1 > /sys/class/backlight/acpi_video0/brightness
	echo -n ''
	bget
}

badj () {
	new=`echo $(cat /sys/class/backlight/acpi_video0/brightness) $1 | bc`
	bound $new
	bset "$?"
}

bget () { cat /sys/class/backlight/acpi_video0/brightness; }

bup () { badj '+1'; }
bdn () { badj '-1'; }
blo () { bset $bmin; }
bhi () { bset $bmax; }

case "$1" in
	bup|bdn|blo|bhi|bget|bset|badj) $@ ;;
	"") ;;
	*) echo "err" ;;
esac