brightness.sh

#!/bin/bash

# Define environment variables
MAX_BRIGHTNESS=100
MIN_BRIGHTNESS=20
BRIGHTNESS_STEPS=10
curBright=$(ybacklight -get | rev | cut -c5- | rev)

function brightUp() {
	if [ "$curBright" = "$MAX_BRIGHTNESS" ]; then
		echo "Current Brightness: " $curBright
	  echo "Brightness is already at maximum"
	elif [ $((curBright + BRIGHTNESS_STEPS)) -ge $MAX_BRIGHTNESS ]; then
	  ybacklight -set 100
	  echo "Brightness has been set to 100"
	elif [ $((curBright + BRIGHTNESS_STEPS)) > $MAX_BRIGHTNESS ]; then
	  ybacklight -inc 10
	  echo "Brightness has been incremented"
	fi
}

function brightDown() {
	if [ "$curBright" = "$MIN_BRIGHTNESS" ]; then
		echo "Current Brightness: " $curBright
	  echo "Brightness is already at minimum"
	elif [ $((curBright - BRIGHTNESS_STEPS)) -ge $MIN_BRIGHTNESS ]; then
	 ybacklight -set 20
	 echo "Brightness has been set to 20"
	elif [ $((curBright - BRIGHTNESS_STEPS)) > $MIN_BRIGHTNESS ]; then
	  ybacklight -dec 10
	  echo "Brightness has been decremented"
	fi
}

while [[ "$1" = --* ]]; do
    unset arg
    if [[ "$1" = *=* ]]; then
        arg="${1//=*/}"
        shift
    else
        arg="$1"
        shift
    fi

    case "$arg" in
        --brightness-up)
            brightUp
            ;;
        --brightness-down)
        		brightDown
        		;;
        --get-brightness)
        		getCurBright
        		;;
        *)
            echo "Unrecognised option: $arg" >&2
            exit 1
            ;;
    esac
done