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

my $t = Time::Piece->strptime ($ARGV[0], '%d/%m/%Y');
printf "Date as supplied: %s\n", $t->dmy ('/');
$t = $t - 86400;
printf "Date minus one day: %s\n", $t->dmy ('/');