# File lib/webrick/httpauth/htgroup.rb, line 37
      def flush(output=nil)
        output ||= @path
        tmp = Tempfile.new("htgroup", File::dirname(output))
        begin
          @group.keys.sort.each{|group|
            tmp.puts(format("%s: %s", group, self.members(group).join(" ")))
          }
          tmp.close
          File::rename(tmp.path, output)
        rescue
          tmp.close(true)
        end
      end