Eric shows a complicated regular expression, but I don't think it will match just --, because this line provides nothing to match the "." and "[^B]", etc.
Instead of these ballooning regexps, how about just using Chael Hall's standardized "end of body" marker? Even if some people had to add it manually to each message, well, that's not a big deal. But I suspect that the people who have sigs being added by BBS software are going to have trouble adding strange header lines, even if they have the regexp expertise to construct them. Anyone who does control their sig, but doesn't want to take the trouble to include it only some of the time, can just add the marker. People might even be able to convince BBS sysops to add it to their autosigs. Or if this just looks too cluttered, maybe the sig-clipper header could just be "Signature-Lines:" -- clip that many, or none by default, and you're done.
Hal
PGP 2 key by finger or e-mail Eli ebrandt@jarthur.claremont.edu