# File lib/cgi/session.rb, line 413
      def update
        return unless @hash
        begin
          f = File.open(@path, File::CREAT|File::TRUNC|File::RDWR, 0600)
          f.flock File::LOCK_EX
          for k,v in @hash
            f.printf "%s=%s\n", CGI::escape(k), CGI::escape(String(v))
          end
        ensure
          f.close unless f.nil?
        end
      end