anchor.diff:  
     final String hash = getGitOutput('rev-parse HEAD', 'Get git hash for $commit');
   
  -  runGit('tag v$version', 'tag the commit with the version label');
  +  runGit('tag $version', 'tag the commit with the version label');
   
     // PROMPT
   
  
positive.code:       parts[0] += 1;
        parts[1] = 0;
        parts[2] = 0;
        break;
      case kY:
        parts[1] += 1;
        parts[2] = 0;
        break;
      case kZ:
        parts[2] += 1;
        break;
      default:
        print('Unknown increment level. The valid values are "$kX", "$kY", and "$kZ".');
        exit(1);
    }
    version = parts.join('.');
  
    if (justPrint) {
      print(version);
  
negative.code:       'to the "dev" channel.');
      stdout.write('Are you? [yes/no] ');
      if (stdin.readLineSync() != 'yes') {
        runGit('tag -d $version', 'remove the tag you did not want to publish');
        print('The dev roll has been aborted.');
        exit(0);
      }
    }
  
    runGit('push $origin $version', 'publish the version');
    runGit('push $origin HEAD:dev', 'land the new version on the "dev" branch');
    print('Flutter version $version has been rolled to the "dev" channel!');
  }
  
  String getFullTag() {
    return getGitOutput(
      'describe --match *.*.*-dev.*.* --first-parent --long --tags',
      'obtain last released version number',
    );
  }
  
  Match parseFullTag(String version) {
    final RegExp versionPattern = RegExp(r'^([0-9]+)\.([0-9]+)\.([0-9]+)-dev\.([0-9]+)\.([0-9]+)-([0-9]+)-g([a-f0-9]+)$');
    return versionPattern.matchAsPrefix(version);
  }
  
  String getVersionFromParts(List<int> parts) {
    assert(parts.length == 5);
    final StringBuffer buf = StringBuffer()
      ..write(parts.take(3).join('.'))
      ..write('-dev.')
      ..write(parts.skip(3).join('.'));
    return buf.toString();
  }
  
  String getGitOutput(String command, String explanation) {
  