use strict;
use warnings;

use Getopt::Long;
my $luckynumber = undef;

sub main {
	GetOptions("luckynumber=i" => \$luckynumber) or die("GetOptions failed");
	die "missing argument luckynumber" unless defined($luckynumber);
	print "Lucky number is " . $luckynumber . "\n";
}

# See also perldoc -f caller
main() if! caller();

1;