1MH-MAIL(5)                    File Formats Manual                   MH-MAIL(5)
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NAME

6       mh-mail - message format for nmh message system
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DESCRIPTION

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
13       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
18       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
22       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
31            From: Local Mailbox <user@example.com>
32            To:
33            cc:
34            Fcc: +outbox
35            Subject:
36
37       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
42       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
49       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
57       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
61       Following is a list of header components that are considered meaningful
62       to various nmh programs.
63
64       Date:
65            Added by post, contains date and time of the message's entry  into
66            the mail transport system.
67
68       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
79       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
85       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
90       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
98       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
103       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
108       To:
109            Contains addresses of primary recipients.
110
111       cc:
112            Contains addresses of secondary recipients.
113
114       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
119       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
126       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
131       Message-ID:
132            A  unique  message  identifier added by post if the -msgid flag is
133            set.
134
135       Subject:
136            Sender's commentary.  It is displayed by scan.
137
138       In-Reply-To:
139            A commentary line added by repl when replying to a message.
140
141       Resent-Date:
142            Added when redistributing a message by post.
143
144       Resent-From:
145            Used instead of the “From:” header when post redistributes a  mes‐
146            sage.  See “From:”.
147
148       Resent-To:
149            New recipients for a message resent by dist.
150
151       Resent-cc:
152            Still more recipients.  See “cc:” and “Resent-To:”.
153
154       Resent-Bcc:
155            Even more recipients.  See “Bcc:” and “Resent-To:”.
156
157       Resent-Fcc:
158            Copy resent message into a folder.  See “Fcc:” and “Resent-To:”.
159
160       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
164       Resent:
165            Annotation for dist under the -annotate option.
166
167       Forwarded:
168            Annotation for forw under the -annotate option.
169
170       Replied:
171            Annotation for repl under the -annotate option.
172
173       Attach:
174            Used by mhbuild to specify a filename to attach to  this  message.
175            See mhbuild(1) for more information.
176

FILES

178       /var/mail/$USER     Location of mail drop.
179

SEE ALSO

181       Standard for the Format of ARPA Internet Text Messages (RFC 822)
182

CONTEXT

184       None
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188nmh-1.7.1                         2014-01-08                        MH-MAIL(5)
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