The qmail Handbook

safecat reliably delivers a message to a maildir mailbox. It's useful for filing messages using filters such as Procmail. For example, the following recipe files all messages in $HOME/Maildir:

:0w |safecat Maildir/tmp Maildir/new

safecat was written by Len Budney, who maintains a Web page for it (http://www.pobox.com/~lbudney/linux/software/safecat.html).