Script to get brightness notification with dunst.

brightness.sh

#!/bin/bash

# You can call this script like this:
# $./brightness.sh up
# $./brightness.sh down

# Based on sebastiencs' script (https://gist.github.com/sebastiencs/5d7227f388d93374cebdf72e783fbd6a)

function get_brightness {
    xbacklight -get
}

function send_notification {
    brightness=`get_brightness`
    brightness=${brightness%%.*}
    # Make the bar with the special character  (it's not dash -) Make sure it's not replaced by '?'
    # https://en.wikipedia.org/wiki/Box-drawing_character
    bar=$(seq -s "─" $(($brightness / 5)) | sed 's/[0-9]//g')
    #Send the notification
	case $brightness in
		100)
		dunstify -i audio-brightness-muted-blocking -r 2593 -t 1000 -u normal "Brightness  $brightness:     $bar"
		;;
		*)
		dunstify -i audio-brightness-muted-blocking -r 2593 -t 1000 -u normal "Brightness   $brightness:      $bar"
		;;
	esac
}

case $1 in
    up)
	xbacklight -inc 5
    send_notification
	;;
    down)
    xbacklight -dec 5
	send_notification
	;;
esac