Using this example you should be able to format it any way you'd like. POSIX should be included in your distro, so you wont need to install a module.

#!/usr/bin/perl
use strict;
use warnings;

use POSIX qw(strftime);

my $today = time;
my $yesterday = $today - 60 * 24 * 60;
my $formatted = strftime "%m/%d/%Y", ( localtime($yesterday) );
print "yesterday = $formatted\n";
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update
What zaxo said...