That's how I'm doing it right now.

But this way the system behaves like three different, independant apps, this is good - I can stop, start, restart any part of it, and bad - it's three different daemons, and when I hand out maintainance to someone else I need to explain the inner workings of the system - it doesen't behave like a single system to them.

It's a bit like hmm, say, Oracle database, it consist of various important parts, and I would prefer it to behave more like single daemon, like apache webserver.

If I would merge this into single binary, that forks itself to handle various tasks, I would loose ability to easily manage those parts. So this is how it would look like with apps split into two parts:

my $child=fork();
die "Can't fork: $!" unless defined $child;
    if ($child) {
      handle_task_one();
    } else {
      handle_task_two();
    }
[download]

Looks almost ok... but now with three parts:

my $child=fork();
die "Can't fork: $!" unless defined $child;
    if ($child) {
      handle_task_one();
    } else {
      my $childschild=fork();
      die "Can't fork: $!" unless defined $childschild;
      if ($childschild) {
      handle_task_two();
      } else {
        handle_task_two();
      }
    }
[download]

Now it becomes unreadable. I got away with it when I created pool of worker 'threads', but with different functions I would prefer my code to look a little better.