@Override
    public void execute() throws IOException {
      super.execute();

      String[] args = cmdline == null ? null : cmdline.getArgs();
      if (args == null || (args.length != 2)) {
        System.err
          .println("ERROR: wrong number of arguments: " + (args == null ? null : args.length));
        printUsage();
        throw new IOException(INCORRECT_USAGE);
      }

      String[] backupIds = args[1].split(",");
      if (backupIds.length < 2) {
        String msg = "ERROR: can not merge a single backup image. "
          + "Number of images must be greater than 1.";
        System.err.println(msg);
        throw new IOException(msg);

      }
      Configuration conf = getConf() != null ? getConf() : HBaseConfiguration.create();
      try (final Connection conn = ConnectionFactory.createConnection(conf);
        final BackupAdminImpl admin = new BackupAdminImpl(conn)) {
        admin.mergeBackups(backupIds);
      }
    }
Command requires consistent state of a backup system Backup system may become inconsistent
because of an abnormal termination of a backup session or delete command
@return true, if yes
hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/impl/BackupCommands.java