private int parseHistoryLength() throws IOException {
      String value = cmdline.getOptionValue(OPTION_RECORD_NUMBER);
      try {
        if (value == null) {
          return DEFAULT_HISTORY_LENGTH;
        }

        return Integer.parseInt(value);
      } catch (NumberFormatException e) {
        System.out.println("Illegal argument for history length: " + value);
        printUsage();
        throw new IOException(INCORRECT_USAGE);
      }
    }
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