anchor.diff:  }
   
   main([List<String> args]) {
  -  ArgParser parser = new ArgParser();
  -  parser.addOption(
  -      'output',
  +  ArgParser parser = ArgParser();
  +  parser.addOption('output',
         abbr: 'o',
         help: 'Output file for tags (default: stdout)',
         valueHelp: 'FILE');
  -  parser.addFlag('follow-links', help: 'Follow symbolic links (default: false)', negatable: false);
  -  parser.addFlag(
  -      'include-hidden',
  -      help: 'Include hidden directories (default: false)',
  -      negatable: false);
  -  parser.addFlag(
  -      'line-numbers',
  +  parser.addFlag('follow-links',
  +      help: 'Follow symbolic links (default: false)', negatable: false);
  +  parser.addFlag('include-hidden',
  +      help: 'Include hidden directories (default: false)', negatable: false);
  +  parser.addFlag('line-numbers',
         abbr: 'l',
         help: 'Add line numbers to extension fields (default: false)',
         negatable: false);
  -  parser.addFlag('skip-sort', help: 'Skip sorting the output (default: false)', negatable: false);
  +  parser.addFlag('skip-sort',
  +      help: 'Skip sorting the output (default: false)', negatable: false);
     parser.addFlag('help', abbr: 'h', help: 'Show this help', negatable: false);
     ArgResults options = parser.parse(args);
     if (options['help']) {
  
positive.code:         lines.sort();
        }
        if (options['output'] != null) {
          new File(options['output']).writeAsString(lines.join('\n'));
        } else {
          print(lines.join('\n'));
        }
  
negative.code:         }
        }).toList();
      } else if (type == FileSystemEntityType.FILE) {
        return Future.value([parseFile(new File(name))]);
      } else if (type == FileSystemEntityType.LINK && options['follow-links']) {
        return addFileSystemEntity(Link(name).targetSync());
      }
    }
  
  