mh-mime(7mh) - man - phpMan

MH-MIME(7mh)                                                                            MH-MIME(7mh)



NAME
       mh-mime - overview of nmh MIME message composition and display

DESCRIPTION
       The  acronym  MIME  stands  for Multipurpose Internet Mail Extensions, the format of Internet
       messages used to send multi-media content.  The nmh command suite has support for the display
       and  composition  of  MIME  messages, but currently MIME support is not completely integrated
       into all tools.  This document provides an overview as to which tools  support  MIME  message
       display, storage, and composition.

   Local Character Set Conversion
       All  of  the  nmh  commands  convert non-native character sets to the local character set, as
       specified by the operating system locale settings.  See locale(1) for more details on the en‐
       vironment  variables used to set the local character set.  Character set conversion will only
       take place if nmh was built with iconv(3) support.  See the mhparam(1) man page  for  how  to
       determine whether your nmh installation includes iconv(3) support.

       Depending on the source and target character set, it may not be possible to convert all char‐
       acters to the local character set.  In this case a substitution character will  be  used  for
       the characters that cannot be converted.

   Message Display
       The  default  format  used by scan(1) will automatically decode MIME-encoded headers.  If you
       have a custom scan format, see the examples provided with the nmh distribution (found in  the
       “/etc/nmh”  directory) and mh-format(5) for details on how to make sure your MIME headers are
       properly decoded.

       By default, if show detects that it is reading a MIME message it will invoke mhshow(1).   The
       default  behavior of mhshow is to only display text parts that are not marked as attachments.
       See mhshow(1) for details on how to control what mhshow will display.

   Message Interrogation and Storage
       The mhlist(1) command will display a listing of the MIME parts contained  within  a  message.
       That information can be used in conjunction with the mhstore command to save individual parts
       or content types of a message.  See mhlist(1) and mhstore(1) for more details  on  how  these
       commands work.

   Message Composition and Reply
       All  messages  sent  by  send(1)  will  automatically be processed by mhbuild(1) before being
       passed to post(1) for message submission.  mhbuild will use the locale settings to mark  text
       content  with the appropriate character set and apply any necessary encoding.  If you wish to
       include text in your message using a character set that does not match your locale, you  will
       need  to specify the character set using an mhbuild directive; see mhbuild(1) for more infor‐
       mation.

       For attaching files or composing other non-text content, there are two  options:  the  attach
       system and mhbuild directives.

       The  attach system is best suited for content where one or more files are being attached to a
       message.  You can use the attach system by either using the attach command at the “What now?”
       prompt,  or  by inserting an “Attach:” header in the message draft containing the name of the
       file you wish to attach to the message (note that all the attach command  does  is  place  an
       “Attach:”  header  in the message draft).  mhbuild will then automatically include the speci‐
       fied file(s) in the outgoing message.  See send(1) for details on how mhbuild determines  the
       proper content type of attached files.

       The  other method of composing MIME messages is to use mhbuild directives.  This allows exact
       control over the contents and format of the MIME message, but has a more complicated  syntax.
       mhbuild(1)  contains details on the directive syntax and examples of directives for different
       media types.  It is important to note that when using mhbuild directives the  user  must  run
       mhbuild  outside  of  send  to have it process directives; when being run by send, mhbuild is
       configured to not process directives so normal user text is not  mistaken  for  a  directive.
       When  using  directives  a  user typically uses the mime command at the “What now?” prompt to
       process them.

       When replying to messages using repl(1) the traditional MH method of including  the  original
       text  in  the  reply  does  not  interoperate with MIME messages.  The -convertargs switch to
       repl(1)   provides   one   solution.     Another    solution:     the    contrib    directory
       (/usr/share/doc/nmh/contrib)  contains  a  Perl  program called replyfilter which will decode
       text parts and present them in an appropriate manner to be included in a message reply.   See
       the  comments at the top of replyfilter for instructions on how to configure nmh to work with
       it.

   Message Rewrite
       The mhfixmsg(1) command can apply various transformations to MIME messages, including  decod‐
       ing  of  text  parts, converting the character set of text parts, and insertion of text/plain
       parts to correspond to text parts of other subtypes.  mhfixmsg can  also  repair  defects  in
       MIME messages, such as mismatched top-level boundary indicators and invalid Content-Transfer-
       Encoding values.

SEE ALSO
       comp(1), iconv(3), mh-format(5) mhbuild(1), mhfixmsg(1), mhparam(1), nmh(7),  repl(1),  what‐
       now(1),
       /usr/share/doc/nmh/contrib/replyfilter,
       /usr/share/doc/nmh/contrib/replaliases

BUGS
       MIME support should be more integrated into all of the nmh tools than it currently is.



nmh-1.7.1                                    2014-12-15                                 MH-MIME(7mh)