- substr: documentation ( source)
- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$base_url = 'http://seos.bolseo.ru/index.php?module=1&page=sape_projects_list/';
if(preg_match ('/.\/+$/i', $base_url))
$base_url = substr ($base_url, 0, -1);
var_dump($base_url);