Magento - remove trailing slash from urls

Open app\code\core\Mage\Core\Block/Abstract.php and find the getUrl() method, it should just be one line of code that returns the requested URL:

return $this->_getUrlModel()->getUrl($route, $params);

Replace that line with the following:

$return_url = $this->_getUrlModel()->getUrl($route, $params);

if ($return_url != $this->getBaseUrl() && substr($return_url, -1) == '/' && !Mage::getSingleton('admin/session')->isLoggedIn()):

    return substr($return_url, 0, -1);

else:

    return $return_url;

endif;