#!/usr/bin/perl -wT
use strict;
use Time::Piece;

my $date    = "10/24/2000";
my $daysago = 1;
my $format  = "%m/%d/%Y";
my $newdate =
  ( Time::Piece->strptime( $date, $format ) - $daysago * 24*60*60 )
  ->strftime($format);

print "$date - $daysago => $newdate\n";

__END__

10/24/2000 - 1 => 10/23/2000