Mbox

mbox is a format for an e-mail spool[?] in which the messages are concatenated with a "From " line at the beginning of each. It requires file locking[?] to prevent the mail delivery program from delivering new messages while the mail reader is deleting them, thus corrupting the file. If the string "From " occurs at the beginning of any line in the body, preceded by at least 0 greater-than signs, one more greater-than sign must be added to prevent it being taken as a message boundary.

Example:

From microsoft.outlook.imo@ixazon.dynip.com Sat Aug 03 2002
Received: from ... by ... with ESMTP;
Subject: Nonsense
From: <build.9.0.2416@ixazon.dynip.com>
To: <junkdtectr@carolina.rr.com>

>From ancient times, people have been writing letters.
From someoneelse@loa.invalid Sun Aug 04 2002
Received: from ... by ... with SMTP
Subject: Iggeret
To: <you@aoeu.snth>

Ha iggeret hazot niktava blashon ivrit.