On Fri, Jan 30, 2026 at 03:08:23PM -0500, Derek Martin wrote:
The original mbox, from 1974, escapes every message line that starts with
"From ", and recognizes an mbox From_ line anywhere, not only after
an empty
line. That's the best-known variant of mbox, and many implementations still
do that.
I'm curious, can you point to one?
Off the top of my head, a delivery agent named fdm. When I looked at
its source code a few years ago, it found mbox From_ lines only by
searching for "From " at the beginning of any line. That's the original
algorithm. Of course, it will fail for other variants. Fdm also writes
original mbox.
Few programs read only one variant of mbox, though. Most, like Mutt,
attempt to read all of them. Most of them only write one variant, again
like Mutt. Writing original mbox is common, I think, though offhand I
don't remember specifically who does it. Writing original mbox is
fairly safe -- it's likely to be read correctly by almost any mbox
software (if the From_ line has a common syntax). Hmm...I think GNU
mailutils used to write original mbox, before it switched to the Rahul
Dhesi variant a couple years ago.
That piece by Zawinski does not acknowledge the existence of original mbox.
It does actually, further in.
Oh, you mean this?
There's a lot of software that thinks the delimiter is
``\nFrom .*\n''. After all, there's no official document
describing the format, so every implementor over the years has
had to guess, to rediscover it for themselves.
Well, kind of, I guess. He doesn't acknowledge this was the original,
though; in fact he implies that Berkeley (BSD) mbox was the original,
and that this is just an accidental mutation of it. Maybe Zawinski
didn't know this was the original.
