#/usr/bin/perl -l
use POSIX 'strftime';
use Time::Local 'timelocal_nocheck';

my ($d, $m, $y) = (localtime)[3,4,5];
my $yesterday   = timelocal_nocheck 0, 0, 0, $d - 1,   $m, $y;
my $fivehundred = timelocal_nocheck 0, 0, 0, $d + 500, $m, $y;

print "Today:       ", strftime "%Y%m%d", localtime;
print "Yesterday:   ", strftime "%Y%m%d", localtime $yesterday;
print "In 500 days: ", strftime "%Y%m%d", localtime $fivehundred;

__END__
Today:       20041001
Yesterday:   20040930
In 500 days: 20060213