backlight_command

Enable backlight command key for i3wm (if xbacklight command cannot working)

1. save the backlight.sh into your i3 config directory
2. chmod +x backlight.sh

in your i3 config file set binding key command with:

# Screen Brightness Controls
# increase brightness
bindsym XF86MonBrightnessUp exec --no-startup-id echo "<yourpassword>" | sudo -S ~/<i3 config dir>/backlight.sh inc 500

# decrease brightness
bindsym XF86MonBrightnessDown exec --no-startup-id echo "<yourpassword>" | sudo -S ~/<i3 config dir>/backlight.sh dec 500

change with your linux system password or root password