1MH-MAIL(5) File Formats Manual MH-MAIL(5)
2
6 mh-mail - message format for nmh message system
7
9 nmh processes messages in a particular format. It should be noted that
10 although neither Bell nor Berkeley mailers produce message files in the
11 format that nmh prefers, nmh can read message files in that format.
12 Each user possesses a mail drop which initially receives all messages
14 processed by post. inc will read from that mail drop and incorporate
15 new messages found there into the user's own mail folders (typically
16 “+inbox”). The mail drop consists of one or more messages.
17 Messages are expected to consist of lines of text. Graphics and binary
19 data are not handled. No data compression is accepted. All text is
20 clear ASCII 7-bit data.
21 The general “memo” framework of RFC 822 is used. A message consists of
23 a block of information in a rigid format, followed by general text with
24 no specified format. The rigidly formatted first part of a message is
25 called the header, and the free-format portion is called the body. The
26 header must always exist, but the body is optional. These parts are
27 separated by an empty line, i.e., two consecutive newline characters.
28 Within nmh, the header and body may be separated by a line consisting
29 of dashes:
30 From: Local Mailbox <user@example.com>
32 To:
33 cc:
34 Fcc: +outbox
35 Subject:
36 The header is composed of one or more header items. Each header item
38 can be viewed as a single logical line of ASCII characters. If the
39 text of a header item extends across several real lines, the continua‐
40 tion lines are indicated by leading spaces or tabs.
41 Each header item is called a component and is composed of a keyword or
43 name, along with associated text. The keyword begins at the left mar‐
44 gin, may not contain spaces or tabs, may not exceed 63 characters (as
45 specified by RFC 822), and is terminated by a colon (`:'). Certain
46 components (as identified by their keywords) must follow rigidly
47 defined formats in their text portions.
48 The text for most formatted components (e.g., “Date:” and “Mes‐
50 sage-Id:”) is produced automatically. The only ones entered by the
51 user are address fields such as “To:”, “cc:”, etc. Internet addresses
52 are assigned mailbox names and host computer specifications. The rough
53 format is “local@domain”, such as “MH@UCI”, or “MH@UCI-ICSA.ARPA”.
54 Multiple addresses are separated by commas. A missing host/domain is
55 assumed to be the local host/domain.
56 As mentioned above, a blank line (or a line of dashes) signals that all
58 following text up to the end of the file is the body. No formatting is
59 expected or enforced within the body.
60 Following is a list of header components that are considered meaningful
62 to various nmh programs.
63 Date:
65 Added by post, contains date and time of the message's entry into
66 the mail transport system.
67 From:
69 This header is filled in by default with the system's idea of the
70 user's local mailbox. This can be changed with the Local-Mailbox
71 profile entry. It contains the address of the author or authors
72 (may be more than one if a “Sender:” field is present). For a
73 standard reply (using repl), the reply address is constructed by
74 checking the following headers (in this order): “Mail-Reply-To:”,
75 “Reply-To:”, “From:”, “Sender:”. A “From:” header MUST exist when
76 the message is sent to post, otherwise the message will be
77 rejected.
78 Envelope-From:
80 Used by post to specify a value for the sender's envelope address
81 to the mail transport system. If omitted, post will use the value
82 of the “Sender:” or the “From:” header. See send(1) for more
83 details.
84 Mail-Reply-To:
86 For a standard reply (using repl), the reply address is con‐
87 structed by checking the following headers (in this order): “Mail-
88 Reply-To:”, “Reply-To:”, “From:”, “Sender:”.
89 Mail-Followup-To:
91 When making a “group” reply (using repl -group), any addresses in
92 this field will take precedence, and no other reply address will
93 be added to the draft. If this header is not available, then the
94 return addresses will be constructed from the “Mail-Reply-To:”, or
95 “Reply-To:”, or “From:”, along with adding the addresses from the
96 headers “To:”, “cc:”, as well as adding your personal address.
97 Reply-To:
99 For a standard reply (using repl), the reply address is con‐
100 structed by checking the following headers (in this order): “Mail-
101 Reply-To:”, “Reply-To:”, “From:”, “Sender:”.
102 Sender:
104 Required by post in the event that the message has multiple
105 addresses on the “From:” line. It is otherwise optional. This
106 line should contain the address of the actual sender.
107 To:
109 Contains addresses of primary recipients.
110 cc:
112 Contains addresses of secondary recipients.
113 Bcc:
115 Still more recipients. However, the “Bcc:” line is not copied
116 onto the message as delivered, so these recipients are not listed.
117 nmh uses an encapsulation method for blind copies, see send(1).
118 Dcc:
120 Still more recipients. However, the “Dcc:” line is not copied
121 onto the messages as delivered. Recipients on the “Dcc:” line
122 receive the same message as recipients on the “To:” and “cc:”
123 lines. See send(1) for more details. Dcc is not supported with
124 the sendmail/pipe mail transport method.
125 Fcc:
127 Causes post to copy the message into the specified folder for the
128 sender, if the message was successfully given to the transport
129 system.
130 Message-ID:
132 A unique message identifier added by post if the -msgid flag is
133 set.
134 Subject:
136 Sender's commentary. It is displayed by scan.
137 In-Reply-To:
139 A commentary line added by repl when replying to a message.
140 Resent-Date:
142 Added when redistributing a message by post.
143 Resent-From:
145 Used instead of the “From:” header when post redistributes a mes‐
146 sage. See “From:”.
147 Resent-To:
149 New recipients for a message resent by dist.
150 Resent-cc:
152 Still more recipients. See “cc:” and “Resent-To:”.
153 Resent-Bcc:
155 Even more recipients. See “Bcc:” and “Resent-To:”.
156 Resent-Fcc:
158 Copy resent message into a folder. See “Fcc:” and “Resent-To:”.
159 Resent-Message-Id:
161 A unique identifier glued on by post if the -msgid flag is set.
162 See “Message-Id:” and “Resent-To:”.
163 Resent:
165 Annotation for dist under the -annotate option.
166 Forwarded:
168 Annotation for forw under the -annotate option.
169 Replied:
171 Annotation for repl under the -annotate option.
172 Attach:
174 Used by mhbuild to specify a filename to attach to this message.
175 See mhbuild(1) for more information.
176
178 /var/mail/$USER Location of mail drop.
179
181 Standard for the Format of ARPA Internet Text Messages (RFC 822)
182
184 None
185nmh-1.7.1 2014-01-08 MH-MAIL(5)