update.php

<?php
/**
 * This script allows to update any directory from its repository if one exists.
 *
 * Setup:
 *  1. Upload update.php file into wp-content directory
 *  2. Make update.php executable
 *  3. Add the following rewrite rule to your .htaccess at the top
 *      RewriteRule ^(.*)update$ /wp-content/update.php?path=$1 [QSA,PT]
 *
 */
require_once( '../wp-load.php' );

if ( !is_user_logged_in() ) auth_redirect();
if ( !current_user_can('update_core') ) {
    echo "You do not have permissions to perform this action";
    die();
}

$target = dirname(WP_CONTENT_DIR) .'/'. $_GET['path'];

if ( !is_dir($target.'/.hg') ) {
    echo 'This directory does not have a repository';
    die();
}

chdir($target);

printf('<pre>%s</pre>', shell_exec('/usr/local/bin/hg pull -u'));