Run wp_install() as an output script in an Alfred 2 Workflow

installing.php

<?php

$site = $_GET['q'];

$dir = "/Users/MYUSERNAME/Sites/$site";
$siteUrl = "http://sites.dev/$site";
$username = 'MYUSERNAME';
$email = 'MYEMAIL';
$password = 'MYPASSWORD';

define( 'WP_SITEURL', $siteUrl );
define( 'WP_INSTALLING', true );

require_once ( $dir . '/wp-load.php' );
require_once ( $dir . '/wp-admin/includes/upgrade.php' );
require_once ( $dir . '/wp-includes/wp-db.php' );
$result = wp_install( $site, $username, $email, true, null, $password );