I just noticed that you use Mozilla under windows. Well, my litle
scripts will not help you there :-(
And netscape/mozilla adds an odd From_ line, where the e-mail address
is replaced by a - (minus). You could make a grep after 'From: ' but
this is strange because some people use names, some don't. Some uses
8bits characters which get changed to some other stuff, etc. I don't
know any easy way... You could try to use Return-Path, or Sender, or
Reply-To, but none of those are mandatory, so you may not find it.