#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11152433
use warnings;
use Time::Piece;
use Time::Seconds;

{
print "DAY is first, then MONTH. That is: DD/MM/YYYY\n";

@ARGV = '01/05/2023'; # DAY comes first

my $t = Time::Piece->strptime("$ARGV[0] 12", "%d/%m/%Y %H");
my $daybefore = ($t - ONE_DAY)->dmy("/");
printf <<END, $ARGV[0], $daybefore;
Date  as  supplied: %s
Date minus one day: %s

END
}

{
print "MONTH is first, then DAY. That is: MM/DD/YYYY\n";

@ARGV = '05/01/2023'; # MONTH comes first

my $t = Time::Piece->strptime("$ARGV[0] 12", "%m/%d/%Y %H");
my $daybefore = ($t - ONE_DAY)->mdy("/");
printf <<END, $ARGV[0], $daybefore;
Date  as  supplied: %s
Date minus one day: %s

END
}

##</code><code>##

DAY is first, then MONTH. That is: DD/MM/YYYY
Date  as  supplied: 01/05/2023
Date minus one day: 30/04/2023

MONTH is first, then DAY. That is: MM/DD/YYYY
Date  as  supplied: 05/01/2023
Date minus one day: 04/30/2023