# File lib/couchrest/helper/streamer.rb, line 28
    def open_pipe(cmd, &block)
      first = nil
      IO.popen(cmd) do |f|
        first = f.gets # discard header
        while line = f.gets 
          row = parse_line(line)
          block.call row unless row.nil? # last line "}]" discarded
        end
      end
      parse_first(first)
    end