How to make brightness work with i3

i3-brightness.md

Install brightnessctl https://www.archlinux.org/packages/community/x86_64/brightnessctl/

Add this script to ~/.config/i3/config

bindsym XF86MonBrightnessUp exec brightnessctl s +10% > /dev/null && notify-send Brightness $(($(brightnessctl get) * 10 / 937 * 10))% -h string:x-canonical-private-synchronous:brightness_percentage --app-name System
bindsym XF86MonBrightnessDown exec brightnessctl s 10%- > /dev/null && notify-send Brightness $(($(brightnessctl get) * 10 / 937 * 10))% -h string:x-canonical-private-synchronous:brightness_percentage --app-name System

explanation:

• bindsym: i3 script to bind key
• XF86MonBrightnessUp brightness up button
• XF86MonBrightnessDown brightness down button
• exec i3 script to execute command
• brightnessctl program that can change brightness by changing the backlight not the brightness of the image
• s argument that stands for set, that can accept + and -
• > forward the output to /dev/null
• && execute another command in same event
• notify-send send notify
• Brightness title of the notification
• $(($(brightnessctl get) * 10 / 937 * 10))% the brightness percentage, i can't make it work to cast the number to decimal using dots, so i multiply the number with 10 instead
• -h string:x-canonical-private-synchronous:brightness_percentage bring tag to the notification so if user change brightness multiple times will not stack the notification but replace the old one instead.
• --app-name System name of the notification