code: private String[] parseGeneralOptions(Options opts, Configuration conf, 
        String[] args) {
      opts = buildGeneralOptions(opts);
      CommandLineParser parser = new GnuParser();
      try {
        commandLine = parser.parse(opts, args, true);
        processGeneralOptions(conf, commandLine);
        return commandLine.getArgs();
      } catch(ParseException e) {
        LOG.warn("options parsing failed: "+e.getMessage());
  
        HelpFormatter formatter = new HelpFormatter();
        formatter.printHelp("general options are: ", opts);
      }
      return args;
    }
docs: Parse the user-specified options, get the generic options, and modify
  configuration accordingly
  @param conf Configuration to be modified
  @param args User-specified arguments
  @return Command-specific arguments