What is wrong with my procmailrc

[Alexander Borghgraef]

 I have included the following lines in my procmailrc (as described in 
the bogofilter man-page), but it doesn't seem to be doing anything:

:0HBc:
* ? bogofilter
mail/spam

 Now, I did some tests with spam mails which made it through the filter.
Obviously, for some the filter hasn't been trained sufficiently yet, but
there were some which gave a positive result:

cat spamtest | bogofilter -v
X-Bogosity: Yes, tests=bogofilter, spamicity=0.999948, version=0.13.5

 Another test I did was negating the bogofilter output in the procmailrc
file, copying all the good files to mail/spam. This worked like a charm.
So I wonder, what is the standard output by bogofilter? It obviously isn't
1/0, so is it the spamicity? When I do cat spamtest | bogofilter, it 
doesn't seem to return anything to stdout, so how does it work?

--
Alexander Borghgraef
Vakgroep Telecommunicatie en Informatieverwerking Tel: +32-(0)9-264 34 16
Universiteit Gent                                 Fax: +32-(0)9-264 42 95
St-Pietersnieuwstraat 41, B-9000 Gent, Belgium    email: ab at telin.ugent.be