code: public static void error(String str) {
      	switch (ZAP.getProcessType()) {
      	case cmdline:	System.err.println(str); break;
      	default:		// Ignore
      	}
      	// Always write to the log
  		logger.error(str);
      }
docs: A method for reporting error messages in {@link CommandLineListener#execute(CommandLineArgument[])} implementations.
  It ensures that messages are written to the log file and/or written to stderr as appropriate.
  @param str the error message