The mail filter/mail delivery agent from the Courier Mail suite
maildrop is a replacement for a local mail delivery agent. maildrop reads a
mail message from standard input, then delivers the message to an mailbox.
maildrop knows how to deliver mail to mbox-style mailboxes and maildirs.
"maildir" is a mailbox format used by Courier, Qmail and Postfix.
maildrop optionally reads instructions from a file, which describe how to
filter incoming mail. These instructions can direct maildrop to deliver the
message to an alternate mailbox, or forward it somewhere else. Unlike procmail,
maildrop uses a structured filtering language.
maildrop is written in C++, and is significantly larger than procmail. However,
much more efficiently. Unlike procmail, it uses resources better and will not
read a 10 megabyte mail message into memory, but save large messages in a
temporary file, and then get filtered. If the standard input to maildrop is a
file, and not a pipe, a temporary file will not be necessary.
maildrop checks the mail delivery instruction syntax from the filter file
before attempting to deliver a message. Unlike procmail, if the filter file
contains syntax errors, maildrop terminates without delivering the message. The
user can fix the typo without causing any mail to be lost.
There is no official package available for openSUSE Leap 15.3