Automatically enable numlock on login screen

numlock.sh

#!/bin/bash
# script to automatically enable numlock on login screen
# tested on Ubuntu 14.04

if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root" 
   exit 1
fi

echo "Updating reps..."
sudo apt-get -qq update
echo "Installing numlockx..."
sudo apt-get install numlockx

if [ -w /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf ]; then
	echo "# enable numlock" >> /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf
	echo "greeter-setup-script=/usr/bin/numlockx on" >> /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf

	echo "Success!"
else
	echo "File /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf does not exist or is not writeable"
fi