code: public static void logLevel(String[] args, AlluxioConfiguration alluxioConf)
        throws ParseException, IOException {
      CommandLineParser parser = new DefaultParser();
      CommandLine cmd = parser.parse(OPTIONS, args, true /* stopAtNonOption */);
  
      List<TargetInfo> targets = parseOptTarget(cmd, alluxioConf);
      String logName = parseOptLogName(cmd);
      String level = parseOptLevel(cmd);
  
      for (TargetInfo targetInfo : targets) {
        setLogLevel(targetInfo, logName, level);
      }
    }
docs: Implements log level setting and getting.
  
  @param args list of arguments contains target, logName and level
  @param alluxioConf Alluxio configuration
  @exception ParseException if there is an error in parsing