I don't think you've really given us enough to chew. My advice is to just get started with whatever strategy you can come up with; keep it as simple and straight-forward as you can. If that doesn't work out, I doubt you would need more than 100 lines of code before deciding to modify the approach. And if it does work out, you're done without a lot of fretting.

my %actions = (
  greet  => sub { print "Hello world!\n"; },
  growl  => sub { print "Rawwwrrrr!\n";   },
  depart => sub { print "Goodbye!\n";     },
  unrecognized => sub { warn "I don't know how to $_[0].\n"; },
);

while( <DATA> ) {
    chomp;
    if( exists $actions{$_} ) {
        $actions{$_}->();
    }
    else {
        $actions{unrecognized}->($_);
    }
}
__DATA__
greet
growl
whine
depart
[download]

...produces...

Hello world!
Rawwwrrrr!
I don't know how to whine.
Goodbye!
[download]

Without a better understanding of what you're after, all I can provide is this sort of framework for your consideration.