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

Date_Init("Language=French");
say UnixDate(DateCalc(
		 ParseDate("aujourd'hui"),
		 $_ . " jours plus tard") , '%A') for (1..7);

__END__

$ perl test.pl
mardi
mercredi
jeudi
vendredi
samedi
dimanche
lundi