phpnuxbill/system/controllers/logout.php

<?php
/**
* PHP Mikrotik Billing (www.phpmixbill.com)
* Ismail Marzuqi <iesien22@yahoo.com>
* @version		5.0
* @copyright	Copyright (C) 2014-2015 PHP Mikrotik Billing
* @license		GNU General Public License version 2 or later; see LICENSE.txt
* @donate		PayPal: iesien22@yahoo.com / Bank Mandiri: 130.00.1024957.4
**/
if (session_status() == PHP_SESSION_NONE) session_start();
session_destroy();
header('location: index.php');