docs: def record_timestamp(pathname_full):
      """Record the timestamp of running in a dotfile."""
      if Settings.test or Settings.list_only or not Settings.record_timestamp:
          return
      if not Settings.follow_symlinks and os.path.islink(pathname_full):
          if Settings.verbose:
              print('Not setting timestamp because not following symlinks')
          return
      if not os.path.isdir(pathname_full):
          if Settings.verbose:
              print('Not setting timestamp for a non-directory')
          return
  
      record_filename_full = os.path.join(pathname_full, RECORD_FILENAME)
      try:
          with open(record_filename_full, 'w'):
              os.utime(record_filename_full, None)
          if Settings.verbose:
              print("Set timestamp: {}".format(record_filename_full))
          for fname in OLD_TIMESTAMPS:
              if fname.startswith(pathname_full) and \
                 fname != record_filename_full:
                  # only remove timestamps below the curent path
                  # but don't remove the timestamp we just set!
                  os.remove(fname)
                  if Settings.verbose:
                      print('Removed old timestamp: {}'.format(fname))
      except IOError:
          print("Could not set timestamp in {}".format(pathname_full))