{
    "mode": "man",
    "parameter": "mh-mail",
    "section": "5",
    "url": "https://www.chedong.com/phpMan.php/man/mh-mail/5/json",
    "generated": "2026-09-04T02:11:43Z",
    "sections": {
        "NAME": {
            "content": "mh-mail - message format for nmh message system\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "nmh processes messages in a particular format.  It should be noted that although neither Bell\nnor  Berkeley mailers produce message files in the format that nmh prefers, nmh can read mes‐\nsage files in that format.\n\nEach user possesses a mail drop which initially receives all messages processed by post.  inc\nwill read from that mail drop and incorporate new messages found there into  the  user's  own\nmail folders (typically “+inbox”).  The mail drop consists of one or more messages.\n\nMessages are expected to consist of lines of text.  Graphics and binary data are not handled.\nNo data compression is accepted.  All text is clear ASCII 7-bit data.\n\nThe  general  “memo” framework of RFC 822 is used.  A message consists of a block of informa‐\ntion in a rigid format, followed by general text with no specified format.  The rigidly  for‐\nmatted  first  part  of a message is called the header, and the free-format portion is called\nthe body.  The header must always exist, but the body is optional.  These parts are separated\nby an empty line, i.e., two consecutive newline characters.  Within nmh, the header and  body\nmay be separated by a line consisting of dashes:\n\nFrom: Local Mailbox <user@example.com>\nTo:\ncc:\nFcc: +outbox\nSubject:\n\nThe header is composed of one or more header items.  Each header item can be viewed as a sin‐\ngle  logical  line  of ASCII characters.  If the text of a header item extends across several\nreal lines, the continuation lines are indicated by leading spaces or tabs.\n\nEach header item is called a component and is composed of a keyword or name, along with asso‐\nciated text.  The keyword begins at the left margin, may not contain spaces or tabs, may  not\nexceed  63 characters (as specified by RFC 822), and is terminated by a colon (`:').  Certain\ncomponents (as identified by their keywords) must follow rigidly  defined  formats  in  their\ntext portions.\n\nThe text for most formatted components (e.g., “Date:” and “Message-Id:”) is produced automat‐\nically.  The only ones entered by the user are address fields such as “To:”, “cc:”, etc.  In‐\nternet addresses are assigned mailbox names and host computer specifications.  The rough for‐\nmat is “local@domain”, such as “MH@UCI”, or “MH@UCI-ICSA.ARPA”.  Multiple addresses are sepa‐\nrated by commas.  A missing host/domain is assumed to be the local host/domain.\n\nAs  mentioned above, a blank line (or a line of dashes) signals that all following text up to\nthe end of the file is the body.  No formatting is expected or enforced within the body.\n\nFollowing is a list of header components that are considered meaningful to various  nmh  pro‐\ngrams.\n\nDate:\nAdded  by  post,  contains  date and time of the message's entry into the mail transport\nsystem.\n\nFrom:\nThis header is filled in by default with the system's idea of the user's local  mailbox.\nThis  can  be  changed with the Local-Mailbox profile entry.  It contains the address of\nthe author or authors (may be more than one if a “Sender:” field  is  present).   For  a\nstandard  reply (using repl), the reply address is constructed by checking the following\nheaders (in this order): “Mail-Reply-To:”, “Reply-To:”, “From:”, “Sender:”.   A  “From:”\nheader  MUST  exist  when the message is sent to post, otherwise the message will be re‐\njected.\n\nEnvelope-From:\nUsed by post to specify a value for the sender's envelope address to the mail  transport\nsystem.   If  omitted,  post  will use the value of the “Sender:” or the “From:” header.\nSee send(1) for more details.\n\nMail-Reply-To:\nFor a standard reply (using repl), the reply address is constructed by checking the fol‐\nlowing headers (in this order): “Mail-Reply-To:”, “Reply-To:”, “From:”, “Sender:”.\n\nMail-Followup-To:\nWhen making a “group” reply (using repl -group), any addresses in this field  will  take\nprecedence,  and  no  other reply address will be added to the draft.  If this header is\nnot available, then the return addresses will be constructed from the  “Mail-Reply-To:”,\nor  “Reply-To:”,  or  “From:”,  along  with adding the addresses from the headers “To:”,\n“cc:”, as well as adding your personal address.\n\nReply-To:\nFor a standard reply (using repl), the reply address is constructed by checking the fol‐\nlowing headers (in this order): “Mail-Reply-To:”, “Reply-To:”, “From:”, “Sender:”.\n\nSender:\nRequired by post in the event that the message has multiple  addresses  on  the  “From:”\nline.   It  is  otherwise  optional.  This line should contain the address of the actual\nsender.\n\nTo:\nContains addresses of primary recipients.\n\ncc:\nContains addresses of secondary recipients.\n\nBcc:\nStill more recipients.  However, the “Bcc:” line is not copied onto the message  as  de‐\nlivered, so these recipients are not listed.  nmh uses an encapsulation method for blind\ncopies, see send(1).\n\nDcc:\nStill  more recipients.  However, the “Dcc:” line is not copied onto the messages as de‐\nlivered.  Recipients on the “Dcc:” line receive the same message as  recipients  on  the\n“To:”  and  “cc:”  lines.   See send(1) for more details.  Dcc is not supported with the\nsendmail/pipe mail transport method.\n\nFcc:\nCauses post to copy the message into the specified folder for the sender, if the message\nwas successfully given to the transport system.\n\nMessage-ID:\nA unique message identifier added by post if the -msgid flag is set.\n\nSubject:\nSender's commentary.  It is displayed by scan.\n\nIn-Reply-To:\nA commentary line added by repl when replying to a message.\n\nResent-Date:\nAdded when redistributing a message by post.\n\nResent-From:\nUsed instead of the “From:” header when post redistributes a message.  See “From:”.\n\nResent-To:\nNew recipients for a message resent by dist.\n\nResent-cc:\nStill more recipients.  See “cc:” and “Resent-To:”.\n\nResent-Bcc:\nEven more recipients.  See “Bcc:” and “Resent-To:”.\n\nResent-Fcc:\nCopy resent message into a folder.  See “Fcc:” and “Resent-To:”.\n\nResent-Message-Id:\nA unique identifier glued on by post if the -msgid flag is set.  See  “Message-Id:”  and\n“Resent-To:”.\n\nResent:\nAnnotation for dist under the -annotate option.\n\nForwarded:\nAnnotation for forw under the -annotate option.\n\nReplied:\nAnnotation for repl under the -annotate option.\n\nAttach:\nUsed  by  mhbuild  to  specify a filename to attach to this message.  See mhbuild(1) for\nmore information.\n",
            "subsections": []
        },
        "FILES": {
            "content": "/var/mail/$USER     Location of mail drop.\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "Standard for the Format of ARPA Internet Text Messages (RFC 822)\n",
            "subsections": []
        },
        "CONTEXT": {
            "content": "None\n\nnmh-1.8                                      2014-01-08                                 MH-MAIL(5mh)",
            "subsections": []
        }
    },
    "summary": "mh-mail - message format for nmh message system",
    "flags": [],
    "examples": [],
    "see_also": []
}