#!/usr/bin/perl
use warnings;
use strict;

MyApp->new->run;

package MyApp;
use base qw(CGI::Application);
use CGI::Application::Plugin::AutoRunmode;

sub mySub : Runmode {
  return "Hello from mySub\n";
}

##</code><code>##

$ ./runmode.cgi rm=mySub
Content-Type: text/html; charset=ISO-8859-1

Hello from mySub