#!/usr/bin/env bash
brightnessctl -me | cut -d, -f4 | tr -d '%'
device=$(brightnessctl -m | head -n 1 | cut -d, -f1)
while true; do
  inotifywait /sys/class/backlight/"$device"/brightness &>/dev/null
  brightnessctl -me | cut -d, -f4 | tr -d '%'
done