MHN(1)                 BSD Reference Manual                MHN(1)       Example entries might be:            mhn-store-text: %m%P.txt            mhn-store-audio/basic: | raw2audio -e ulaw -s 8000 -c 1 > %m%P.au            mhn-store-application/PostScript: %m%P.ps       Further,  note that when asked to store a content contain-       ing a partial message, _m_h_n will try to locate all  of  the       portions and combine them accordingly.  Thus, if someone's       sent you a message in several parts, you  might  put  them       all in their own folder and do:            mhn all -store       This will store exactly one message, containing the sum of       the parts.  Note that if _m_h_n can not locate each part,  it       will not store anything.       Finally,  if  the  `-auto' switch is given and the content       contains information indicating the filename  the  content       should  be  stored  as  (and if the filename doesn't begin       with a '/'), then the filename from the  content  will  be       used instead.   EExxtteerrnnaall AAcccceessss       For  contents  of type message/external-body, _m_h_n supports       these access-types:            afs            anon-ftp            ftp            local-file            mail-server       For the "anon-ftp" and "ftp" access types, if your  system       supports  a SOCKETs interface to TCP/IP, then _m_h_n will use       a built-in FTP client.  Otherwise, _m_h_n will look  for  the       mmhhnn--aacccceessss--ffttpp profile entry, e.g.,            mhn-access-ftp: myftp.sh       to  determine the pathname of a program to perform the FTP[mh.6]                        MH.6.8                            7MHN(1)                 BSD Reference Manual                MHN(1)       retrieval.  This program is invoked with these arguments:            domain name of FTP-site            username            password            remote directory            remote filename            local filename            "ascii" or "binary"       The program should  terminate  with  a  zero-valued  exit-       status if the retrieval is successful.   TThhee CCoonntteenntt CCaacchhee       When _m_h_n encounters an external content containing a "Con-       tent-ID:" field, and if the content allows  caching,  then       depending  on  the  caching  behavior  of _m_h_n, the content       might be read from or written to a cache.       The  caching  behavior  of  _m_h_n  is  controlled  with  the       `-rcache'  and `-wcache' switches, which define the policy       for reading from, and writing to, the cache, respectively.       One  of four policies may be specified: "public", indicat-       ing that _m_h_n should make use  of  a  publically-accessible       content  cache; "private", indicating that _m_h_n should make       use of the user's private content cache; "never", indicat-       ing that _m_h_n should never make use of caching; and, "ask",       indicating that _m_h_n should ask the user.       There are two directories where contents  may  be  cached:       the  profile  entry mmhhnn--ccaacchhee names a directory containing       world-readable  contents,  and,  the  profile  entry  mmhhnn--       pprriivvaattee--ccaacchhee  names  a  directory containing private con-       tents.  The former should be an absolute  (rooted)  direc-       tory name.  For example,            mhn-cache: /tmp       might  be used if you didn't care that the cache got wiped       after each reboot of the system.   The  latter  is  inter-       preted relative to the user's MH directory, if not rooted,       e.g.,            mhn-private-cache: .cache       (which is the default value).[mh.6]                        MH.6.8                            8MHN(1)                 BSD Reference Manual                MHN(1)   CCaacchhiinngg tthhee CCoonntteennttss       When you encounter a content of type message/external-body       with  access  type  "mail-server", _m_h_n will ask you if may       send a message to a mail-server  requesting  the  content,       e.g.,            % show 1            Retrieve content by asking mail-server@...            SEND file            ? yes            mhn: request sent       Regardless  of  your decision, _m_h_n can't perform any other       processing on the content.       However, if _m_h_n is allowed to request  the  content,  then       when it arrives, there should be a top-level "Content-ID:"       field which corresponds to the value in the original  mes-       sage/external-body   content.   You  should  now  use  the       `-cache' switch to tell _m_h_n to enter the arriving  content       into the content cache, e.g.,            % mhn -cache 2            caching message 2 as file ...       You can then re-process the original message/external-body       content, and "the right thing should happen", e.g.,            % show 1             ...   CCoommppoossiinngg tthhee CCoonntteennttss       The _m_h_n program can also be used as a simple editor to aid       in  composing  multi-media  messages.   When  invoked by a       _w_h_a_t_n_o_w program, _m_h_n will expect the body of the draft  to       be formatted as an "_m_h_n composition file."[mh.6]                        MH.6.8                            9MHN(1)                 BSD Reference Manual                MHN(1)       The syntax of this is straight-forward:               body         ::=     1*(content | EOL)               content      ::=     directive | plaintext               directive    ::=     "#" type "/" subtype                                        0*(";" attribute "=" value)                                        [ "(" comment ")" ]                                        [ "<" id ">" ]                                        [ "[" description "]" ]                                        [ filename ]                                        EOL                                  | "#@" type "/" subtype                                        0*(";" attribute "=" value)                                        [ "(" comment ")" ]                                        [ "<" id ">" ]                                        [ "[" description "]" ]                                        external-parameters                                        EOL                                  | "#forw"                                        [ "<" id ">" ]                                        [ "[" description "]" ]                                        [ "+"folder ] [ 0*msg ]                                        EOL                                  | "#begin"                                          [ "<" id ">" ]                                          [ "[" description "]" ]                                          [   "alternative"                                            | "parallel"                                            | something-else    ]                                          EOL                                        1*body                                    "#end" EOL               plaintext    ::=     [ "Content-Description:"                                          description EOL EOL ]                                        1*line                                    [ "#" EOL ]                                  | "#<" type "/" subtype                                        0*(";" attribute "=" value)                                        [ "(" comment ")" ]                                        [ "[" description "]" ]                                        EOL                                        1*line                                    [ "#" EOL ][mh.6]                        MH.6.8                           10MHN(1)                 BSD Reference Manual                MHN(1)               line         ::=     "##" text EOL                                    -- interpreted as "#"text EOL                                  | text EOL       Basically, the body contains one or more contents.  A con-       tent consists of either a directive, indicated with a  "#"       as  the  first  character of a line; or, plaintext (one or       more lines of text).  The continuation character, "\", may       be used to enter a single directive on more than one line,       e.g.,            #@application/octet-stream; \                type=tar; \                x-conversions=compress       There are four kinds  of  directives:  "type"  directives,       which name the type and subtype of the content; "external-       type" directives, which also name the type and subtype  of       the  content;  the "forw" directive, which is used to for-       ward a digest of messages;  and,  the  "begin"  directive,       which is used to create a multipart content.       For  the  type directives, the user may optionally specify       the name of a file containing  the  contents  in  "native"       (decoded)  format.   (If  the filename starts with the "|"       character, then this gives a command whose output is  cap-       tured  accordingly.)  If a filename is not given, _m_h_n will       look for information in the user's  profile  to  determine       how  the  different  contents should be composed.  This is       accomplished by consulting a composition string, and  exe-       cuting  it  under //bbiinn//sshh, with the standard output set to       the content.  The composition  string  may  contain  these       escapes:            %a  additional arguments            %f  filename containing content            %F  %f, and stdout is not re-directed            %s  subtype       First, _m_h_n will look for an entry of the form:            mhn-compose-<type>/<subtype>       to  determine  the  command to use to compose the content.       If this isn't found, _m_h_n will look for  an  entry  of  the       form:            mhn-compose-<type>       to  determine  the  composition  command.   If  this isn't       found, _m_h_n will complain.[mh.6]                        MH.6.8                           11MHN(1)                 BSD Reference Manual                MHN(1)       An example entry might be:            mhn-compose-audio/basic: record | raw2audio -F       Because commands like these will vary,  depending  on  the       display  environment  used  for login, composition strings       for different contents should probably be put in the  file       specified  by  the  $$MMHHNN  environment variable, instead of       directly in your user profile.       The external-type directives are used to provide a  refer-       ence  to  a  content,  rather  than enclosing the contents       itself.  Hence, instead of providing a  filename  as  with       the  type  directives,  external-parameters  are supplied.       These look like regular parameters, so they must be  sepa-       rated accordingly, e.g.,            #@application/octet-stream; \                type=tar; \                x-conversions=compress [] \                access-type=anon-ftp; \                name="mh-mime.tar.Z"; \                directory="mrose/mh-mime"; \                site="ftp.ics.uci.edu"       By  specifying "[]", an empty description string is given,       and the start of the  external-parameters  is  identified.       These parameters are of the form:            access-type=  usually _a_n_o_n_-_f_t_p or _m_a_i_l_-_s_e_r_v_e_r            name=         filename            permission=   read-only or read-write            site=         hostname            directory=    directoryname (optional)            mode=         usually _a_s_c_i_i or _i_m_a_g_e (optional)            size=         number of octets            server=       mailbox            subject=      subject to send            body=         command to send for retrieval       For  the  forw  directive, the user may optionally specify       the name of the folder and which messages are to  be  for-       warded.  if a folder is not given, it defaults to the cur-       rent folder.  Similarly, if a message  is  not  given,  it       defaults  to  the current message.  Hence, the forw direc-       tive is similar to the _f_o_r_w (1) command, except  that  the       former  uses  the MIME rules for encapsulation rather than       those specified in RFC 934.  Usage  of  the  `-rfc934mode'       switch indicates whether _m_h_n should attempt to utilize the       encapsulation rules in such a way as to  appear  that  RFC[mh.6]                        MH.6.8                           12