In article <9049a7aa-73be-bb47-de4c-5e1a4d9768c0@htt-consult.com> you write:
I am struggling a bit with terminology here. There is the "regular" RFC822 email From: header. I will call that From-header. Then there is the mbox start-of-message From line. I will call that From-mbox.
If I use formail to change various email headers other than the From-Header, formail creates a From-mbox line that shows the sender as what is in the existing From-Header.
Right, that's what it does. Or you can use a -f flag to omit the mbox From altogether
If I user formail to -I replace the From-Header, formail creates a From-mbox line where the sender is foo@bar.
That's the default if there's no valid From: in the incoming message.
But formail should not be getting it wrong in the first place to need procmail to correct it.
It's not wrong even if it's not what you expect. Letting procmail generate the mbox From is a better idea anyway. R's, John