man > mh-mail(5)

MH-MAIL(5mh)                                                                            MH-MAIL(5mh)

NAME
       mh-mail - message format for nmh message system

DESCRIPTION
       nmh processes messages in a particular format.  It should be noted that although neither Bell
       nor  Berkeley mailers produce message files in the format that nmh prefers, nmh can read mes‐
       sage files in that format.

       Each user possesses a mail drop which initially receives all messages processed by post.  inc
       will read from that mail drop and incorporate new messages found there into  the  user's  own
       mail folders (typically “+inbox”).  The mail drop consists of one or more messages.

       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  “memo” framework of RFC 822 is used.  A message consists of a block of informa‐
       tion in a rigid format, followed by general text with no specified format.  The rigidly  for‐
       matted  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 nmh, the header and  body
       may be separated by a line consisting of dashes:

            From: Local Mailbox <user AT example.com>
            To:
            cc:
            Fcc: +outbox
            Subject:

       The header is composed of one or more header items.  Each header item can be viewed as a sin‐
       gle  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 asso‐
       ciated 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., “Date:” and “Message-Id:”) is produced automat‐
       ically.  The only ones entered by the user are address fields such as “To:”, “cc:”, etc.  In‐
       ternet addresses are assigned mailbox names and host computer specifications.  The rough for‐
       mat is “local@domain”, such as “MH@UCI”, or “MH AT UCI-ICSA.ARPA”.  Multiple addresses are sepa‐
       rated 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  nmh  pro‐
       grams.

       Date:
            Added  by  post,  contains  date and time of the message's entry into the mail transport
            system.

       From:
            This header is filled in by default with the system's idea of the user's local  mailbox.
            This  can  be  changed with the Local-Mailbox profile entry.  It contains the address of
            the author or authors (may be more than one if a “Sender:” field  is  present).   For  a
            standard  reply (using repl), the reply address is constructed by checking the following
            headers (in this order): “Mail-Reply-To:”, “Reply-To:”, “From:”, “Sender:”.   A  “From:”
            header  MUST  exist  when the message is sent to post, otherwise the message will be re‐
            jected.

       Envelope-From:
            Used by post to specify a value for the sender's envelope address to the mail  transport
            system.   If  omitted,  post  will use the value of the “Sender:” or the “From:” header.
            See send(1) for more details.

       Mail-Reply-To:
            For a standard reply (using repl), the reply address is constructed by checking the fol‐
            lowing headers (in this order): “Mail-Reply-To:”, “Reply-To:”, “From:”, “Sender:”.

       Mail-Followup-To:
            When making a “group” reply (using repl -group), any addresses in this field  will  take
            precedence,  and  no  other reply address will be added to the draft.  If this header is
            not available, then the return addresses will be constructed from the  “Mail-Reply-To:”,
            or  “Reply-To:”,  or  “From:”,  along  with adding the addresses from the headers “To:”,
            “cc:”, as well as adding your personal address.

       Reply-To:
            For a standard reply (using repl), the reply address is constructed by checking the fol‐
            lowing headers (in this order): “Mail-Reply-To:”, “Reply-To:”, “From:”, “Sender:”.

       Sender:
            Required by post in the event that the message has multiple  addresses  on  the  “From:”
            line.   It  is  otherwise  optional.  This line should contain the address of the actual
            sender.

       To:
            Contains addresses of primary recipients.

       cc:
            Contains addresses of secondary recipients.

       Bcc:
            Still more recipients.  However, the “Bcc:” line is not copied onto the message  as  de‐
            livered, so these recipients are not listed.  nmh uses an encapsulation method for blind
            copies, see send(1).

       Dcc:
            Still  more recipients.  However, the “Dcc:” line is not copied onto the messages as de‐
            livered.  Recipients on the “Dcc:” line receive the same message as  recipients  on  the
            “To:”  and  “cc:”  lines.   See send(1) for more details.  Dcc is not supported with the
            sendmail/pipe mail transport method.

       Fcc:
            Causes post to copy the message into the specified folder for the sender, if the message
            was successfully given to the transport system.

       Message-ID:
            A unique message identifier added by post if the -msgid flag is set.

       Subject:
            Sender's commentary.  It is displayed by scan.

       In-Reply-To:
            A commentary line added by repl when replying to a message.

       Resent-Date:
            Added when redistributing a message by post.

       Resent-From:
            Used instead of the “From:” header when post redistributes a message.  See “From:”.

       Resent-To:
            New recipients for a message resent by dist.

       Resent-cc:
            Still more recipients.  See “cc:” and “Resent-To:”.

       Resent-Bcc:
            Even more recipients.  See “Bcc:” and “Resent-To:”.

       Resent-Fcc:
            Copy resent message into a folder.  See “Fcc:” and “Resent-To:”.

       Resent-Message-Id:
            A unique identifier glued on by post if the -msgid flag is set.  See  “Message-Id:”  and
            “Resent-To:”.

       Resent:
            Annotation for dist under the -annotate option.

       Forwarded:
            Annotation for forw under the -annotate option.

       Replied:
            Annotation for repl under the -annotate option.

       Attach:
            Used  by  mhbuild  to  specify a filename to attach to this message.  See mhbuild(1) for
            more information.

FILES
       /var/mail/$USER     Location of mail drop.

SEE ALSO
       Standard for the Format of ARPA Internet Text Messages (RFC 822)

CONTEXT
       None

nmh-1.8                                      2014-01-08                                 MH-MAIL(5mh)