maildrop is a replacement for your local mail delivery agent. maildrop
reads a mail message from standard input, then delivers the message to
your mailbox. maildrop knows how to deliver mail to mbox-style
mailboxes, and maildirs. "maildir" is a mailbox format used by the Qmail
MTA.

maildrop can optionally read instructions from a file on how to filter
incoming mail, and, based upon the instructions, deliver mail to
alternate mailboxes, or forward it to somewhere else, like procmail.
Unlike procmail, maildrop uses a structured filtering language that's a
bit easier on the eyes.

maildrop is written in C++, and is significantly larger than procmail,
in compiled form. However, it uses resources much more efficiently.
Unlike procmail, maildrop will not read a 10 megabyte mail message into
memory. Large messages are saved in a temporary file, and are filtered
from that file. Files are saved in the user's home directory. If the
standard input to maildrop is a file, not a pipe, no temporary file will
be necessary.

maildrop can be used with sendmail, Qmail, and other MTAs.

WWW: http://www.flounder.net/~mrsam/maildrop/