I was merely trying to locate any source that would define or
systematically describe the layout of Berkley MBOX (Unix mailbox) format.
The Berkley MBOX is legendary, so there must be some document covering it.
Does anyone know where?
I found this in some pine documentation at
http://systems.binghamton.edu/Pine/low-level.html
Berkeley Mail Format
This format comes to us from the ancient UNIX mail program,
/bin/mail. (Note that this doesn't have anything to do with
Berkeley, but we call it the Berkeley mail file format anyway.) This
program was actually used to interactively read mail at one time,
and is still used on many systems as the local delivery agent. In
the Berkeley mail format, a folder is a simple text file. Each
message (including the first) must start with a separator line
which takes approximately the form:
From juser(_at_)u(_dot_)example(_dot_)edu Wed Aug 11 14:32:33 1993
Each message ends with two blank lines. There are actually several
different variations in the date part of the string, twenty at
last count. Because of the format of the separators, lines in
the mail message beginning with "From ", space included, risk
being confused as message separator lines. Some mail programs
will interpret any line beginning with "From " as a message
separator, while others --including Pine-- will not be confused
unless the line really looks like a message separator, complete
with address and date. Such lines will be modified to begin with
">From ". In deference to other mail programs, you may also set the
"save-will-quote-leading-froms" feature, in which case any line
beginning with "From " will be modified as above. If you see this
occasionally in incoming mail messages, the culprit is not Pine
but the message delivery program being used at your site.
You can fool Pine into thinking a file is a mail folder by copying
a suitable message separator from a real folder to the beginning of
the file and wherever you want message boundaries. The vast majority
of INBOXes Pine reads and folders it writes are of this format.
The qmail documentation goes into greater detail:
http://www.qmail.org/qmail-manual-html/man5/mbox.html
However, the general Internet consensus (from various sources) seems to
be that the best spec is the actual V7 /bin/mail source.
Chris