Try this code:

#!/usr/bin/perl -w

use strict;
use LWP::Simple;

my ($content_type, $document_length, $modified_time, $expires, $server
+) = head("http://www.gnu.org/index.html");
$modified_time = localtime($modified_time) if $modified_time;
print "Modified: " . ($modified_time ? $modified_time : "Unknown") . "
+\n";

exit;
[download]

Nothe that modified_time is not available for all web servers/pages.

--dda