anchor.diff:      valueHelp: 'hash',
       defaultsTo: 'upstream/master',
     );
  +  argParser.addOption(
  +    kOrigin,
  +    help: 'Specifies the name of the upstream repository',
  +    valueHelp: 'repository',
  +    defaultsTo: 'upstream',
  +  );
  +  argParser.addFlag(kYes, negatable: false, abbr: 'y', help: 'Skip the confirmation prompt.');
     argParser.addFlag(kHelp, negatable: false, help: 'Show this help message.', hide: true);
     ArgResults argResults;
     try {
  
positive.code:     exit(1);
    }
  
    runGit('fetch upstream', 'fetch upstream');
    runGit('reset $commit --hard', 'check out master branch');
  
    String version = getFullTag();
  
negative.code:   }
  
    final String level = argResults[kIncrement];
    final String commit = argResults[kCommit];
    final String origin = argResults[kOrigin];
    final bool autoApprove = argResults[kYes];
    final bool help = argResults[kHelp];
  
    if (help || level == null) {
  