mh-mail.rf

早期freebsd实现

.\"	@(MHWARNING)
.\" @(#)$Id: mh-mail.rf,v 1.6 1992/05/12 22:23:34 jromine Exp $
.SC MH-MAIL 5
.NA
mh-mail \- message format for MH message system
.SY
any \fIMH\fR command
.DE
\fIMH\fR processes messages in a particular format.
It should be noted that although neither Bell nor Berkeley mailers produce
message files in the format that \fIMH\fR prefers,
\fIMH\fR can read message files in that antiquated format.

Each user possesses a mail drop box which initially receives
all messages processed by \fIpost\fR\0(8).
\fIInc\fR\0(1) will read from that drop box and incorporate the new messages
found there into the user's own mail folders (typically `+inbox').
The mail drop
box consists of one or more messages.
@BEGIN: MMDFMTS
To facilitate the
separation of messages, each message begins and ends with
a line consisting of nothing but four CTRL\-A (octal 001)
characters.
@END: MMDFMTS
@BEGIN: MHMTS
To facilitate the
separation of messages, each message begins and ends with
a line consisting of nothing but four CTRL\-A (octal 001)
characters.
@END: MHMTS

Messages
are expected to consist of lines of text.
Graphics and binary data are not handled.
No data compression is accepted.
All text is clear
ASCII 7-bit data.

The general \*(lqmemo\*(rq framework of RFC\-822 is used.
A message consists of a block of information in a rigid format,
followed by general text with no specified format.
The rigidly formatted first part of a message is called the header,
and the free-format portion is called the body.
The header must always exist, but the body is optional.
These parts are separated by an empty line,
i.e., two consecutive newline characters.
Within \fIMH\fR,
the header and body may be separated by a line consisting of dashes:

.nf
.in +.5i
.ne 10
.eo
.so @(MHETCPATH)/components
.ec
.in -.5i
.fi

The header is composed of one or more header items.
Each header item can be viewed as a single logical line of ASCII
characters.
If the text of a header item extends across several
real lines, the continuation lines are indicated by leading
spaces or tabs.

Each header item is called a component and is composed of a
keyword or name, along with associated text.
The keyword begins at the
left margin, may NOT contain spaces or tabs, may not exceed 63
characters (as specified by RFC\-822), and is terminated by a colon (`:').
Certain
components (as identified by their keywords) must follow rigidly
defined formats in their text portions.

The text for most formatted components
(e.g., \*(lqDate:\*(rq and \*(lqMessage\-Id:\*(rq)
is produced automatically.
The only ones entered by the
user are address fields such as \*(lqTo:\*(rq, \*(lqcc:\*(rq, etc.
Internet addresses
are assigned mailbox names and host computer specifications.
The
rough format is \*(lqlocal@domain\*(rq, such as \*(lqMH@UCI\*(rq,
or \*(lqMH@UCI\-ICSA.ARPA\*(rq.
Multiple addresses are separated by commas.
A missing host/domain is assumed to be the local host/domain.

As mentioned above,
a blank line (or a line of dashes)
signals that all following text up to the end of the file is the body.
No formatting is expected or enforced within the body.

Following is a list of header components that are considered
meaningful to various MH programs.
.in +.5i
.ti -.5i
Date:
.br
Added by \fIpost\fR\0(8),
contains date and time of the message's entry into the transport system.

.ti -.5i
From:
.br
Added by \fIpost\fR\0(8),
contains the address of the author or authors (may be more than one if a
\*(lqSender:\*(rq field is present).
Replies are typically directed to addresses in the \*(lqReply\-To:\*(rq or
\*(lqFrom:\*(rq field (the former has precedence if present).

.ti -.5i
Sender:
.br
Added by \fIpost\fR\0(8)
in the event that the message already has a \*(lqFrom:\*(rq line.
This line contains the address of the actual sender.
Replies are never sent to addresses in the \*(lqSender:\*(rq field.

.ti -.5i
To:
.br
Contains addresses of primary recipients.

.ti -.5i
cc:
.br
Contains addresses of secondary recipients.

.ti -.5i
Bcc:
.br
Still more recipients.
However, the \*(lqBcc:\*(rq line is not copied onto the message as delivered,
so these recipients are not listed.
\fIMH\fR uses an encapsulation method for blind copies, see \fIsend\fR\0(1).

.ti -.5i
Fcc:
.br
Causes \fIpost\fR\0(8) to copy the message into the specified folder for the
sender,
if the message was successfully given to the transport system.

.ti -.5i
Message\-ID:
.br
A unique message identifier added by \fIpost\fR\0(8) if the `\-msgid' flag
is set.

.ti -.5i
Subject:
.br
Sender's commentary.  It is displayed by \fIscan\fR\0(1).

.ti -.5i
In\-Reply\-To:
.br
A commentary line added by \fIrepl\fR\0(1) when replying to a message.

.ti -.5i
Resent\-Date:
.br
Added when redistributing a message by \fIpost\fR\0(8).

.ti -.5i
Resent\-From:
.br
Added when redistributing a message by \fIpost\fR\0(8).

.ti -.5i
Resent\-To:
.br
New recipients for a message resent by \fIdist\fR\0(1).

.ti -.5i
Resent\-cc:
.br
Still more recipients.
See \*(lqcc:\*(rq and \*(lqResent\-To:\*(rq.

.ti -.5i
Resent\-Bcc:
.br
Even more recipients.
See \*(lqBcc:\*(rq and \*(lqResent\-To:\*(rq.

.ti -.5i
Resent\-Fcc:
.br
Copy resent message into a folder.
See \*(lqFcc:\*(rq and \*(lqResent\-To:\*(rq.

.ti -.5i
Resent\-Message\-Id:
.br
A unique identifier glued on by \fIpost\fR\0(8) if the `\-msgid' flag
is set.
See \*(lqMessage\-Id:\*(rq and \*(lqResent\-To:\*(rq.

.ti -.5i
Resent:
.br
Annotation for \fIdist\fR\0(1) under the `\-annotate' option.

.ti -.5i
Forwarded:
.br
Annotation for \fIforw\fR\0(1) under the `\-annotate' option.

.ti -.5i
Replied:
.br
Annotation for \fIrepl\fR\0(1) under the `\-annotate' option.
.in -.5i
.sp
.Fi
^@(MHDROPLOC)~^Location of mail drop
.Pr
None
.Sa
\fIStandard for the Format of ARPA Internet Text Messages\fR (aka RFC\-822)
.De
None
.Co
None
.En