code: def getHeader():
      
      system, host, release, version, machine = os.uname()
  
      return "# UMI-tools version: %s\n# output generated by %s\n# job started at %s on %s -- %s\n# pid: %i, system: %s %s %s %s" %\
             (__version__,
              " ".join(sys.argv),
              time.asctime(time.localtime(time.time())),
              host,
              global_id,
              os.getpid(),
              system, release, version, machine)
docs: return a header string with command line options and timestamp