Stephane Bortzmeyer wrote,
| Always use 'formail -rt' and never 'formail -r'. Because such precedence
| (Sender over From) is an important violation of RFC 822. There is one
| canonical order, described in the RFC and nothing else should be used,
| like fuzzy ranking or, worse, reordering. This is a serious problem with
| formail.
I think that the idea is that formail -r is intended to determine the origi-
nation address, not the place to reply; formail -rt is for determining the
place to send replies. For addressing a response, yes, -rt will invert the
header in a way more in line with the rules; for figuring out the origination
point, formail -rzxTo: might be better than formail -rtzxTo:.
And here's an additional problem: formail -rD always uses the formail -r
precedences; you can't make it use the -rt precedences and the -D cache-
checking function at the same time.