#!/usr/bin/perl
sub _timestamp
{

    my $diff    = shift;


    my ($sec,$min,$hour,$mday,$mon,$year,$wday) = localtime(time - $diff);

$mon++;

    return sprintf("%d-%02d-%02d",($year + 1900),$mon,$mday);
}

$pre=259200;  # 24*60*3
$myTimeStamp = _timestamp ($pre);

print "$myTimeStamp \n";