I would use a dispatch table with a bunch of subroutines, one for each action. The dispatch table makes it easy to use the command line argument to call the proper bit of code. Simple example:

my %ACTION_NAMED = define_actions();

my $action = shift; # First argument
my @args = @ARGV;   # Remaining arguments

if (exists $ACTION_NAMED{$action}) {
  $ACTION_NAMED{$action}->(@args);
}
else {
  $ACTION_NAMED{_default_}->(@args);
}

sub define_actions {
    return (
        action1   => \&action1,
        action2   => \&action2,
        _default_ => \&usage,
    );
}

sub action1 { ... }
sub action2 { ... }
sub usage { ... }
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