PhantomInstaller\Installer::getOS PHP Method

    public function getOS()
    {
        // override the detection of the operation system
        // by checking for an env var and returning early
        if (isset($_ENV['PHANTOMJS_PLATFORM'])) {
            return strtolower($_ENV['PHANTOMJS_PLATFORM']);
        }
        if (isset($_SERVER['PHANTOMJS_PLATFORM'])) {
            return strtolower($_SERVER['PHANTOMJS_PLATFORM']);
        }
        $uname = strtolower(php_uname());
        if (strpos($uname, 'darwin') !== false || strpos($uname, 'openbsd') !== false || strpos($uname, 'freebsd') !== false) {
            return 'macosx';
        } elseif (strpos($uname, 'win') !== false) {
            return 'windows';
        } elseif (strpos($uname, 'linux') !== false) {
            return 'linux';
        } else {
            return 'unknown';
        }
    }