def getline # :nodoc:
      line = @sock.readline # if get EOF, raise EOFError
      line.sub!(/(\r\n|\n|\r)\z/n, "")
      if @debug_mode
        print "get: ", sanitize(line), "\n"
      end
      return line
    end
Reads a line from the sock.  If EOF, then it will raise EOFError