fdm 2.1 MRA and MDA
fdm fetches and delivers mail in various ways.
Mail may be fetched from IMAP or POP3 servers, from local maildirs, or read from standard input. It is then filtered based on regular expressions, its size or age, or the output of a (shell) command. It can be rewritten by an external process, dropped, left on the server or delivered into maildirs, mboxes, to a file or pipe, or any combination.
fdm is primarily designed for use by a single user, but can use privilege separation to safely deliver mail in multi-user setups.