code: private static void printUsage() {
      String prefix = "Usage: hadoop " + UtilizationShell.class.getSimpleName();
      System.err.println(prefix);
      System.err.println("           [-all]");
      System.err.println("           [-cluster]");
      System.err.println("           [-job]");
      System.err.println("           [-job jobID1 jobID2...]");
      System.err.println("           [-tasktracker]");
      System.err.println("           [-tasktracker hostname1 hostname2...]");
      System.err.println("           [-help [cmd]]");
      System.err.println();
      ToolRunner.printGenericCommandUsage(System.err);
    }
docs: Displays format of commands.