Control intel brightness with commands

brightness.sh

#!/usr/bin/env bash

current=$(cat /sys/class/backlight/intel_backlight/brightness)
max=$(cat /sys/class/backlight/intel_backlight/max_brightness)
wanted=$1
stepsize=30

function usage() {
	echo "Usage:"
	echo "Make it higher: brightness higher"
	echo "Make it lower: brightness lower"
	echo "Make it max: brightness max"
	echo "Make it min: brightness min"
	echo "Make it *: brightness *"
}

if [ -z "$wanted" ]; then
	usage
else
	if [ $wanted = 'max' ]; then
		echo $max | sudo tee /sys/class/backlight/intel_backlight/brightness > /dev/null
	elif [ $wanted = 'min' ]; then
		echo '10' | sudo tee /sys/class/backlight/intel_backlight/brightness > /dev/null
	elif [ $wanted = 'lower' ]; then
		if [ `expr $current - $stepsize` -lt $stepsize ]; then
			echo '10' | sudo tee /sys/class/backlight/intel_backlight/brightness > /dev/null
		else
			echo `expr $current - $stepsize` | sudo tee /sys/class/backlight/intel_backlight/brightness > /dev/null
		fi
	elif [ $wanted = 'higher' ]; then
		if [ `expr $current + $stepsize` -gt $max ]; then
			echo $max | sudo tee /sys/class/backlight/intel_backlight/brightness > /dev/null
		else
			echo `expr $current + $stepsize` | sudo tee /sys/class/backlight/intel_backlight/brightness > /dev/null
		fi
	else
		if [ $wanted -eq $wanted 2>/dev/null ]; then
			if [ $wanted -lt 10 ]; then
				echo "That's too low. Use a value between 10 and $max"
			else
				echo $wanted | sudo tee /sys/class/backlight/intel_backlight/brightness > /dev/null
			fi
		else
			usage
		fi
	fi
fi