private function verifyOutput($output) {
        $output = trim($output);
        $result = 'unknown';
        if (preg_match('/: ([^:]+)$/', $output, $matches) ) {
            $result = $matches[1];
        }

        $this->message = $result;

        if (array_key_exists($result, $this->messageStatus) ) {
            $this->status = $this->messageStatus[$result];
        }
        else {
            $this->status = $this->messageStatus['unknown'];
        }

        return ($this->status === 0);
    }