tcp-env.1

linux下qmail的源码 本人加了一些注释

.TH tcp-env 1
.SH NAME
tcp-env \- set up TCP-related environment variables
.SH SYNOPSIS
.B tcp-env
[
.B \-rR
]
[
.B \-t\fItimeout
]
.I program
[
.I arg ...
]
.SH DESCRIPTION
The input for
.B tcp-env
must be a TCP connection.
.B tcp-env
finds out information about that connection,
puts the information into several environment variables
as described in
.B tcp-environ(5),
and runs
.I program
with the given arguments.

Usually
.B tcp-env
is run from
.BR inetd .
It might instead be run from another server
that already sets up the right environment variables;
if
.B PROTO
is set to
.B TCP
when
.B tcp-env
is invoked,
.B tcp-env
assumes that all the other variables are set up properly,
and it does not check whether the input is a TCP connection.
.SH OPTIONS
.TP
.B \-r
(Default.)
Attempt to obtain
.B TCPREMOTEINFO
from the remote host.
.TP
.B \-R
Do not attempt to obtain
.B TCPREMOTEINFO
from the remote host.
.TP
.B \-t\fItimeout
Give up on the
.B TCPREMOTEINFO
connection attempt after
.I timeout
seconds.
Default: 30.
.SH "SEE ALSO"
tcp-environ(5),
inetd(8)