This solution works for both internal and external keyboards running the gnome desktop environment. You can simply copy and paste the text within the adjust_bricghtness.sh and add it to your .bashrc or .zshrc etc for persistence after reboots and upgrades OR
- download the adjust_brightness.sh script
- chmod +x adjust_brightness.sh
- ./adjust_brightness.sh
- ENJOY adjusting your bhrightness form your keyboard. peace h4ck3r5