Do you want to drop the mail into /dev/null after bouncing?
If so, do this:
:0w
*
^(Resent-)?(From|Sender):(.*[^a-zA-Z0-9])?\/soandso(_at_)spam\(_dot_)com
---------------
! $MATCH
I just started to use procmail and I do not understand what the stuff
inside the bracket in your recipe really does, as I could not find anything
in the man pages.
the "[^a-zA-Z0-9]" is part of the regular expression which matches a
non-alphanumeric character. So, the parenthesized expression
(.*[^a-zA-Z0-9])?
matches an abitrary string up to a non-alphanumeric character just
before "soandso...". The purpose is to skip comment strings before the
real address, and to avoid false partial matches.
For expample, it keeps
From: myothersoandso(_at_)spam(_dot_)com
from matching, but does matche these:
From:soandso(_at_)spam(_dot_)com
From: The Greatest Salesman on Earth <soandso(_at_)spam(_dot_)com>
From: (Slick) soandso.spam.com
See the "egrep" man page for details.