try {
            // process command-line arguments
            for (optind = 0; optind < argv.length; ++optind) {
                if (!argv[optind].substring(0,1).equals("-") ||
                  argv[optind].equals("--"))
                    break;    // end of options
                if (argv[optind].equals("-p")) {   // -p port
                    if (++optind >= argv.length) {
                        System.err.println(usage);
                        System.exit(1);
                    }
                    port = (new Integer(argv[optind])).intValue();
                }
                else if (argv[optind].equals("-h")) {   // -h host
                    if (++optind >= argv.length) {
                        System.err.println(usage);
                        System.exit(1);
                    }
                    host = argv[optind];
                }
                else {
                    System.err.println(usage);
                    System.exit(1);
                }
            }
        }
        catch (NumberFormatException e) {
            System.err.println("bad number format");
            System.err.println(usage);
            System.exit(1);
        }