#!/usr/bin/env perl 
use strict;
use warnings;
use Time::Piece;
use POSIX;

my @days = Time::Piece->day_list;
print "Days are @days\n";
setlocale( LC_ALL, 'fr_FR' );
Time::Piece->use_locale ();
@days = Time::Piece->day_list;
print "Days are @days\n";

##</code><code>##

$ perl days.pl 
Days are Sun Mon Tue Wed Thu Fri Sat
Days are dim. lun. mar. mer. jeu. ven. sam.