use warnings;
use strict;
use Getopt::Long;

my @actions;
sub first { push @actions, 'first' }
sub second { push @actions, 'second' }

GetOptions(first=>\&first, second=>\&second)
	or die "Invalid options passed to $0\n";

for my $act (@actions) {
	if ($act eq 'first')
		{ print "First!\n" }
	elsif ($act eq 'second')
		{ print "Second!\n" }
	else { die $act } # shouldn't happen
}

__END__

$ perl 11140961b.pl --first --second --first --second --second --first
First!
Second!
First!
Second!
Second!
First!
$ perl 11140961b.pl --first --second --year --first --second --second --first
Unknown option: year
Invalid options passed to 11140961b.pl