code: def suffix(args):
      
      p = OptionParser(suffix.__doc__)
      p.set_outfile()
      opts, args = p.parse_args(args)
  
      if len(args) != 2:
          sys.exit(not p.print_help())
  
      fastqfile, sf = args
      fw = must_open(opts.outfile, "w")
      nreads = nselected = 0
      for rec in iter_fastq(fastqfile):
          nreads += 1
          if rec is None:
              break
          if rec.seq.endswith(sf):
              print(rec, file=fw)
              nselected += 1
      logging.debug("Selected reads with suffix {0}: {1}".\
                    format(sf, percentage(nselected, nreads)))
docs: %prog suffix fastqfile CAG
  
      Filter reads based on suffix.