Hello morgon,

My favorite is Date::Manip but it is not a core module, but the possibilities are infinite!

If you like it and it looks a bit complicated let me know to help you.

Update: Small sample of code to calculate Friday next week, two weeks after etc. etc...

#!/usr/bin/perl
use strict;
use warnings;
use Date::Manip;
use feature 'say';

my $dateInTwoWeeks = ParseDate("Friday in 2 weeks");
my $unixDate1 = UnixDate($dateInTwoWeeks,"%d-%m-%y");
say $unixDate1;

my $dateTwoWeeksAgo = ParseDate("Friday 2 weeks ago");
my $unixDate2 = UnixDate($dateTwoWeeksAgo,"%d-%m-%y");
say $unixDate2;

my $dateNextFriday = ParseDate("next Friday");
my $unixDate3 = UnixDate($dateNextFriday,"%d-%m-%y");
say $unixDate3;

__END__

$ perl test.pl
09-02-18
12-01-18
02-02-18
[download]

Update 2: Sorry I just noticed your description to your problem. Solution is bellow:

#!/usr/bin/perl
use strict;
use warnings;
use Date::Manip;
use feature 'say';

my $date = ParseDate("Today");
unless (UnixDate($date, "%A") eq "Friday"){
    $date = ParseDate("next Friday");
}
say UnixDate($date,"%d-%m-%y");

=different format
my $date = ParseDate("Today");
$date = ParseDate("next Friday")
    unless (UnixDate($date, "%A") eq "Friday");
say UnixDate($date,"%d-%m-%y");
=cut

__END__

$ perl test.pl
26-01-18
[download]

Hope this helps, BR.