Provided by: qmail_1.06-5_amd64
preline - prepend lines to message
in .qmailext: | preline command
preline feeds each incoming mail message through command. At the top of each message it inserts a UUCP-style From_ line, a Return-Path line, and a Delivered-To line. preline is useful for procmail and ELM's filter, which do not understand the qmail-command environment variables.
-d Do not include the Delivered-To line. You should use this option when the recipient of the incoming mail message is actually under remote control, but was sent here through control/virtualdomains for manual routing. -f Do not include the From_ line. You should use this option except for commands that create mbox files. -r Do not include the Return-Path line.
mbox(5), qmail-command(8) preline(1)