protected function execute($command)
    {
        $process = proc_open($command, array(1 => array('pipe', 'w'), 2 => array('pipe', 'w')), $pipes);
        fclose($pipes[2]);
        $this->output = stream_get_contents($pipes[1]);
        fclose($pipes[1]);
        $status = proc_get_status($process);
        $this->status = $status['exitcode'];
        proc_close($process);
    }