preline.1

linux下qmail的源码 本人加了一些注释

.TH preline 1
.SH NAME
preline \- prepend lines to message
.SH SYNOPSIS
in
.BR .qmail\fIext :
.B | preline \fIcommand
.SH DESCRIPTION
.B preline
feeds each incoming mail message through
.IR command .
At the top of each message it inserts
a UUCP-style
.B From_
line, a
.B Return-Path
line, and a
.B Delivered-To
line.

.B preline
is useful for
.B procmail
and
ELM's
.BR filter ,
which
do not understand the
.B qmail-command
environment variables.
.SH OPTIONS
.TP
.B \-d
Do not include the
.B 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
.B control/virtualdomains
for manual routing.
.TP
.B \-f
Do not include the
.B From_
line. You should use this option except for
.IR command s
that create
.I mbox
files.
.TP
.B \-r
Do not include the
.B Return-Path
line.
.SH "SEE ALSO"
mbox(5),
qmail-command(8)