Before e-mail lies to /var/mail/me
I (as a user) want to preprocess it, for example add some extra headers
depending on its body or something similar.
Under Linux I used procmail for this just because MTA is 
configure in this way by default.

What is the easiest way to do the same under NetBSD+postfix?
I would prefer NOT to use procmail from pkgsrc.
I also have no any knowledge in postfix (it is too big...).

I would be grateful for a simple example.

-- 
Best regards, Aleksey Cheusov.