protected function guessType()
    {
        $os = strtolower(PHP_OS);
        if (false !== strpos($os, 'cygwin')) {
            return self::OS_TYPE_CYGWIN;
        }
        if (false !== strpos($os, 'darwin')) {
            return self::OS_TYPE_DARWIN;
        }
        if (false !== strpos($os, 'bsd')) {
            return self::OS_TYPE_BSD;
        }
        if (0 === strpos($os, 'win')) {
            return self::OS_TYPE_WINDOWS;
        }

        return self::OS_TYPE_UNIX;
    }