05-15-2016, 08:42 PM
If you go into your keyboard settings in the Application Shortcuts tab, add a new shortcut with the command and assign it to whichever keybinding you like. Do that again except change the minus symbol to a plus (+) and assign it to another keybinding. You can change the 10 to a lower/higher number if you want to change the speed at which it changes.
Code:
xbacklight -10