On 2019-06-07 05:08, Frank Watt wrote:
When I look at the headers of most mail, I see an mbox-style From line. Where do we make use of the 'reformat -f0' and "Return-Path" advice?
In the stream of data that ends up on the standard input of the delivery agent (procmail, maildrop, whatever).
If fetchmail -m works the same as an MTA directed by .forward to hand over a message to a delivery agent, then fetchmail sets up a pipe from itself to the delivery agent, so the delivery agent reads a single message on its standard input. Some MTAs precede the message with an mbox-style From_ line; some don't. Fetchmail may or may not add a From_ line.
You can find out by having fetchmail hand the message to a script that you write, which both saves a copy of its stdin and passes it on to a delivery agent. The script would be something like this:
#!/bin/sh tee -a $HOME/fetchmail.test | maildrop
