use strict;
use Date::Calc qw(Delta_YMD Today);

sub version {
    my $format = shift || "%D.%02d.%02d";
    my ($year, $month, $day) = Today;
    my ($dy, $dm, $dd)       = Delta_YMD(1973, 7, 19, $year, $month, $day);

    my $version  = sprintf($format, $dy, $dm, $dd);

    return $version;
};

print version();