Very simple and functinal bash script to adjust brightness for the official 7 inch touchdcreen.
Designed and tested for raspberry pi with official 7 inch touchdcreen.
cd ~/
mkdir github-repo
cd github-repo/
git clone https://github.com/WestleyK/backlight
cd backlight/
sudo ./install.sh
pi@raspberrypi:~ $ backlight-pi help
Usage: simple-backlight [OPTION]
h | help (print help menu)
15-255 (adjust from 15-255)
u | up (adjust up by 20)
d | down (adjust down by 20)
s | sleep (enter sleep mode)
v | version (print version)
Source code: https://github.com/WestleyK/backlight
pi@raspberrypi:~ $