MacLight 
MacLight lets you control the keyboard LEDs on your Mac or Macbook.
Screenshot
Installation
$ gem install maclight
Usage
$ maclight --help
Usage: maclight <command>
MacLight v3.0.0 - LED control utility
Options:
--version: Print version and exit
--help, -h: Show this message
Commands:
keyboard Control keyboard LEDs
API Usage
#!/usr/bin/env ruby
require 'maclight'
# Turn LEDs on
MacLight.all_leds(true)
sleep 2
# Turn LEDs off
MacLight.all_leds(false)Notice
MacLight can currently only toggle all LEDs at once and has only been tested on OSX 10.11.3 (El Capitan).