/\bD\W*U\W*C\W*\K\b/i

would match those occurrences and many others, regardless of the cases
of the letters.  It is a nice little exercise to generate a list of
regexes like that, or a compound regex, from a list of words
automatically.  (map, split, join, eval)

I presume that tr/D/F/ would give a more realistic example.  :-)

One system I heard of did a good job of suppressing bad words until the
dog breeders needed to talk about their {*filter*}es. Another wouldn't let
anyone discuss the region of Scunthorpe in Great Britain. Overkill.

I heard that someone made a closed caption decoder which tried to
substitute nicer words for the bad ones. It sanitized "Dick Van{*filter*}" into
"Jerk Van {*filter*}".

Sure, you could make a program which would strip the punctuation and scan
the rest, but the vandals will still find a way to sneak past with a few
     _ _      _                                 _
  __| (_)_ __| |_ _   _  __      _____  _ __ __| |___
 / _` | | '__| __| | | | \ \ /\ / / _ \| '__/ _` / __|
| (_| | | |  | |_| |_| |  \ V  V / (_) | | | (_| \__ \
 \__,_|_|_|   \__|\__, |   \_/\_/ \___/|_|  \__,_|___/
                  |___/

I suggest that you simply save each day's additions to a file for a human
being to check before appending. Cheers!

hi,

I have created a guest book using perl. I would like to know of a way of
detecting bad words. I currently have the program search for bad words
but some clever users started using spaces, symbols to prevent the
program from catching the bad words. For example assume DUCK is a bad
word. Normally, the guest book will replace it with blank spaces but if
the user types in
D U C K or D*U*C*K or D-U-C-K or D__U__C__K, the program will not catch
it. Is there anyway I can prevent this from happening.

Thanks a lot.

-rahul

That's about all you can do...

People tend to be better at recognising words masked like this than computers.

Consider :

DUK DLICK DU(K DVCK KCUD.

Adding a human to the loop is probably the only way. Even if all that person
does is add new regexes to match bad words based on the ones which are
slipping through.

There is also the problem of false positives.

Foreign words (or English words) which contain 'duck' in them somewhere.
Place names, People's names, etc.

If you much censor things, then bulk deletion of messages with 'bad' words
will probably convince people not to bother.

Such a policy would make it hard to talk about wonderful things like
South Park though.

--
Sam

It has been said before that true filtering is next to impossible.
However, one implementation of a regex might be the following.  Using
negated character classes for what _is_ allowed to be between characters.
This, of course, is far from full proof.

#!/usr/local/bin/perl
use strict;
$|++;

while ( <DATA> ) {
    s/D[^a-z]*U[^a-z]*C[^a-z]*K/ /ig;
    print;

I have createdD a guest book using perl. I would like to know of a way of
detecting bad words. I currently have the program search for bad words
but some clever users started Uusing spaces, symbols to prevent the
program from Ccatching the bad words. For example assume DUCK is a bad
word. Normally, the guest book will replace it with blank spaces but if
the user types in
D U C K or D*U*C*K or D-U-C-K or D__U__C__K, the program will not catch
it. Is there anyway I can prevent this from happening.

Thanks a lot.K

This is a DRUNCK too.

Hello, this DUC'K.