mh-mime(7)

1MH-MIME(7)             Miscellaneous Information Manual             MH-MIME(7)
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NAME

6       mh-mime - overview of nmh MIME message composition and display
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DESCRIPTION

9       The  acronym MIME stands for Multipurpose Internet Mail Extensions, the
10       format of Internet messages used to send multi-media content.  The  nmh
11       command  suite has support for the display and composition of MIME mes‐
12       sages, but currently MIME support is not completely integrated into all
13       tools.   This  document  provides an overview as to which tools support
14       MIME message display, storage, and composition.
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16   Local Character Set Conversion
17       All of the nmh commands convert non-native character sets to the  local
18       character  set,  as  specified by the operating system locale settings.
19       See locale(1) for more details on the environment variables used to set
20       the local character set.  Character set conversion will only take place
21       if nmh was built with iconv(3) support.  See the  mhparam(1)  man  page
22       for  how  to  determine whether your nmh installation includes iconv(3)
23       support.
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25       Depending on the source and target character set, it may not be  possi‐
26       ble to convert all characters to the local character set.  In this case
27       a substitution character will be used for the characters that cannot be
28       converted.
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30   Message Display
31       The  default  format  used  by  scan(1) will automatically decode MIME-
32       encoded headers.  If you have a custom scan format,  see  the  examples
33       provided  with the nmh distribution (found in the “/etc/nmh” directory)
34       and mh-format(5) for details on how to make sure your MIME headers  are
35       properly decoded.
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37       By  default,  if show detects that it is reading a MIME message it will
38       invoke mhshow(1).  The default behavior of mhshow is  to  only  display
39       text  parts  that  are  not  marked  as attachments.  See mhshow(1) for
40       details on how to control what mhshow will display.
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42   Message Interrogation and Storage
43       The mhlist(1) command will display a listing of  the  MIME  parts  con‐
44       tained  within  a message.  That information can be used in conjunction
45       with the mhstore command to save individual parts or content types of a
46       message.   See  mhlist(1)  and mhstore(1) for more details on how these
47       commands work.
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49   Message Composition and Reply
50       All messages  sent  by  send(1)  will  automatically  be  processed  by
51       mhbuild(1)  before  being  passed  to  post(1)  for message submission.
52       mhbuild will use the locale settings to  mark  text  content  with  the
53       appropriate  character  set  and  apply any necessary encoding.  If you
54       wish to include text in your message using a character  set  that  does
55       not match your locale, you will need to specify the character set using
56       an mhbuild directive; see mhbuild(1) for more information.
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58       For attaching files or composing other non-text content, there are  two
59       options: the attach system and mhbuild directives.
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61       The  attach  system  is best suited for content where one or more files
62       are being attached to a message.  You can  use  the  attach  system  by
63       either  using  the  attach  command  at  the  “What now?” prompt, or by
64       inserting an “Attach:” header in the message draft containing the  name
65       of the file you wish to attach to the message (note that all the attach
66       command does is place  an  “Attach:”  header  in  the  message  draft).
67       mhbuild  will  then  automatically include the specified file(s) in the
68       outgoing message.  See send(1) for details on  how  mhbuild  determines
69       the proper content type of attached files.
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71       The  other  method  of composing MIME messages is to use mhbuild direc‐
72       tives.  This allows exact control over the contents and format  of  the
73       MIME  message,  but has a more complicated syntax.  mhbuild(1) contains
74       details on the directive syntax and examples of directives for  differ‐
75       ent  media  types.   It  is  important  to note that when using mhbuild
76       directives the user must run mhbuild outside of send to have it process
77       directives;  when  being  run  by  send,  mhbuild  is configured to not
78       process directives so normal user text is not mistaken for a directive.
79       When  using  directives  a  user typically uses the mime command at the
80       “What now?” prompt to process them.
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82       When replying to messages using repl(1) the traditional  MH  method  of
83       including  the  original  text  in the reply does not interoperate with
84       MIME messages.  The -convertargs switch to repl(1) provides  one  solu‐
85       tion.       Another      solution:       the      contrib     directory
86       (/usr/share/doc/nmh/contrib) contains a Perl program called replyfilter
87       which  will decode text parts and present them in an appropriate manner
88       to be included in a message reply.  See the  comments  at  the  top  of
89       replyfilter for instructions on how to configure nmh to work with it.
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91   Message Rewrite
92       The  mhfixmsg(1) command can apply various transformations to MIME mes‐
93       sages, including decoding of text parts, converting the  character  set
94       of  text parts, and insertion of text/plain parts to correspond to text
95       parts of other subtypes.  mhfixmsg can also repair defects in MIME mes‐
96       sages,  such  as  mismatched  top-level boundary indicators and invalid
97       Content-Transfer-Encoding values.
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BUGS

106       MIME  support  should be more integrated into all of the nmh tools than
107       it currently is.
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111nmh-1.7.1                         2014-12-15                        MH-MIME(7)

NAME

DESCRIPTION

SEE ALSO

BUGS