iftoccfrom [ addr ... ]
The iftoccfrom program reads an 822-format message from standard input and matches address in the To, Cc, or From headers against addr. If it finds a match, iftoccfrom exits 0. Otherwise it exits 100. If no addr argument is present, then iftoccfrom uses the address in the environment variable $RECIPIENT as addr.
If it encounters a temporary error while reading input, iftoccfrom exits 111.
The .qmail line
| condtomaildir dir iftoccfrom afriend
writes correspondence with afriend to dir.
William Baxter <email@example.com>