code: def main(argv=None):
    
  
    if argv is None:
      argv = sys.argv
  
    try:
      opts, args = getopt.getopt(argv[1:], 'dhs', ['nodelay', 'help', 'size'])
    except getopt.error as msg:
      raise Usage(msg)
  
    # Print usage and return, regardless of presence of other args.
    for opt, _ in opts:
      if opt in ('-h', '--help'):
        print(__doc__)
        print(help_msg)
        return 0
  
    isdelay = False
    for opt, _ in opts:
      # Prints the size of the terminal and returns.
      # Mutually exclusive to the paging of text and overrides that behaviour.
      if opt in ('-s', '--size'):
        print('Length: %d, Width: %d' % TerminalSize())
        return 0
      elif opt in ('-d', '--delay'):
        isdelay = True
      else:
        raise Usage('Invalid arguments.')
  
    # Page text supplied in either specified file or stdin.
  
    if len(args) == 1:
      with open(args[0]) as f:
        fd = f.read()
    else:
      fd = sys.stdin.read()
    Pager(fd, delay=isdelay).Page()
docs: Routine to page text or determine window size via command line.