Even though you talk about "Diff'ing", you don't want the (minimal) set of changes to get from one file to the second, you only want to know whether two files are identical or not (or that's the interpretation I lay into your words).

There are several ways to achieve what you want. The easiest way would be to use Digest::MD5, which comes with Perl 5.6 in the core. If the two files have an identical MD5 hash, they most likely are the same.

If your version of Perl dosen't have Digest::MD5, you might want do do the check manually, first checking whether the two files have the same file size (via the tell function or the -s function (perldoc -f -X), and then slurping the two files into memory and doing an eq comparision on them.

If the files are too large to be held in memory at one time, you might want to compare little chunks of the two files one at a time, starting either from the beginning or the end of the file, whichever part has the more likely chance of being different.

perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ;    # The  
$d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider
($c = $d->accept())->get_request(); $c->send_response( new   #in the
HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' #  web
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