static function run_interactive($cmd)
    {
        $descriptors = array(
          0 => array ("file", "php://stdin", "r"),
          1 => array ("file", "php://stdout", "w"),
          2 => array ("file", "php://stdout", "w")
        );
        $process = proc_open($cmd, $descriptors, $pipes);
        if (is_resource($process)) {
          $return_value = proc_close($process);
          return $return_value;
        }
    }