GNU Mailutils
	General-Purpose Mail Package	Official GNU Software

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3.19 MH — The MH Message Handling System

The primary aim of this implementation is to provide an interface between Mailutils and Emacs using mh-e module.

To use Mailutils MH with Emacs, add the following line to your site-start.el or .emacs file:

(load "mailutils-mh")

For the information about the current state of Mailutils MH implementation please refer to file mh/TODO in the Mailutils distribution directory.

3.19.1 Major differences between Mailutils MH and other MH implementations

1. Sequence numbers increase monotonically;

   Message sequence numbers are used as UIDs and thus increase monotonically. This means, in particular, that if your inbox has messages in the range ‘X--Y’ and you delete all messages and then incorporate new mail, the first incorporated message will be assigned sequence number ‘Y + 1’ (other MH implementations will assign ‘1’). If this behavior bugs you, add the following setting to your .mh_profile:

   Volatile-uidnext: true
   

   You can always renumber your messages starting from ‘1’ by running

   folder -pack=1
   

2. UUCP addresses are not supported;
3. Mailutils supports a set of new format specifications (see Format String Diffs);
4. Mailutils provides a set of new profile variables (see Profile Variable Diffs);
5. All programs recognize --help and --version options

   These options are recognized only if no other arguments are present in the command line. Abbreviations are not recognized. This makes Mailutils MH implementation compatible with the standard usage for GNU tools.

6. Several programs behave differently (see Program Diffs);

3.19.1.1 New and Differing MH Format Specifications

MH Format: string decode (string str)

Decodes the input string str as per RFC 2047. Useful in printing ‘From:’, ‘To:’ and ‘Subject:’ headers.

Notice that, unlike the similar NMH function, decode checks the value of the global profile variable Charset (see Charset variable) to determine the charset to output the result in. If this variable is not set, decode returns its argument without any change. If this variable is set to auto, decode tries to determine the charset name from the setting of LC_ALL environment variable. Otherwise, the value of Charset is taken to be the name of the character set.

MH Format: string package ()

Returns package name (string ‘mailutils’).

MH Format: string package_string ()

Returns full package string (e.g. ‘GNU Mailutils 2.1’)

MH Format: string version ()

Returns mailutils version.

MH Format: string unre (string str)

The function removes any leading whitespace and eventual ‘Re:’ prefix from its argument. Useful for creating subjects in reply messages:

  %<{subject}Subject: Re: %(unre{subject})\\n%>

MH Format: void reply_regex (string r)

Sets the regular expression used to recognize reply messages. The argument r should be a POSIX extended regular expression. Matching is case insensitive.

For example, the following invocation

  %(reply_regex ^\(re|aw|ang|odp\)\(\\[[0-9]+\\]\)?:[[:blank:]])

corresponds to English ‘Re’, Polish ‘Odp’, Norwegian ‘Aw’ or German ‘Ang’, optionally followed by a number in brackets, followed by colon and any amount of whitespace. Notice proper quoting of the regex metacharacters.

See also Reply-Regex (see Reply-Regex variable) and isreply (see isreply MH function) below.

MH Format: boolean isreply ([string str])

If str is not given, the value of ‘Subject:’ header is taken.

The function returns true if its argument matches the “reply subject” regular expression. This expression is set via the global profile variable Reply-Regex (see Reply-Regex variable) or via the format function reply_regex.

This function is useful for creating ‘Subject:’ headers in reply messages. For example, consider the following construction:

%<{subject}%(lit)%<(isreply)%?\
(profile reply-prefix)%(concat)%|%(concat Re:)%>\
%(concat{subject})%(printhdr Subject: )\n%>

If the ‘Subject:’ header already contained reply prefix, this construct leaves it unchanged. Otherwise it prepends to it the value of Reply-Prefix profile variable, or, if it is unset, the string ‘Re:’.

This expression is used in default replcomps and replgroupcomps files.

MH Format: boolean rcpt (‘to’ | ‘cc’ | ‘me’ | ‘all’)

This function returns true if the given element is present in the recipient mask (as modified by -cc or -nocc options) and false otherwise. It is used in default formats for repl and comp, e.g.:

%(lit)%<(rcpt to)%(formataddr{to})%>

Notice that this means that usual replcomps file will be ignoring -cc and -nocc options, unless it has been modified as shown above.

MH Format: string concat ()

Appends whitespace + arg to string register.

MH Format: string printhdr (string str)

Prints the value of string register, prefixed by str. The output is formatted as a RFC 822 header, i.e. it is split at whitespace characters nearest to the width boundary and each subsequent segment is prefixed with horizontal tabulation.

MH Format: string in_reply_to ()

Generates the value for ‘In-reply-to:’ header according to RFC 2822.

MH Format: string references ()

Generates the value for ‘References:’ header according to RFC 2822.

3.19.1.2 New MH Profile Variables

Variable: MH Variable string Charset

Controls the character set in which the components decoded via the decode (see decode function) format function should be output.

Variable: MH Variable string Reply-Regex

Keeps the regular expression used to recognize reply messages. The argument should be a POSIX extended regular expression. Matching is case insensitive.

For more information, please see See reply_regex function.

3.19.1.3 Differences in MH Program Behavior

anno

The prompt in interactive mode is ‘Component name:’, instead of ‘Enter component name:’ displayed by the RAND anno.

If a -component field is not specified and standard input is not connected to a terminal, anno does not display the prompt before reading the component from the standard input. RAND anno displays the prompt anyway.

burst

The utility is able to burst both RFC 934 digest messages and MIME multipart messages. It provides two additional command line options: -recurse and -length.

The -recurse option instructs the utility to recursively expand the digest.

The -length option can be used to set the minimal encapsulation boundary length for RFC 934 digests. Default length is 1, i.e. encountering one dash immediately following a newline triggers digest decoding. It is OK for messages that follow RFC 934 specification. However, many user agents do not precisely follow it, in particular, they often do not escape lines starting with a dash by ‘- ’ sequence. Mailman is one of such agents. To cope with such digests you can set encapsulation boundary length to a higher value. For example, bounce -length 8 has been found to be sufficient for most Mailman-generated digests.

comp

Understands -build option.

fmtdump

This command is not provided. Use fmtcheck instead.

inc

• The -moveto option. The -moveto option instructs inc to move messages into another folder after incorporating them. This option has effect only if the -truncate option has also been specified and the underlying mailbox supports the ‘move’ operation. Currently only ‘imap’ and ‘imaps’ mailboxes support it. For example, the following command moves incorporated messages into the ‘archive’ folder:

  inc -file imaps://imap.gmail.com -moveto=archive
  

  The ‘moveto’ URL parameter can be used instead of this option, e.g.:

  inc -file 'imaps://imap.gmail.com;moveto=archive'
  

• Multiple sources Mailutils inc is able to incorporate messages from several source mailboxes. These are specified via multiple -file options, e.g.:

  inc  -truncate \
       -file 'imaps://imap.gmail.com;moveto=archived' \
       -file pops://mail.gnu.org \
       -file /var/mail/root
  

• URL parameters The following additional parameters can be used in the mailbox URLs supplied with the -file option:

  moveto=folder

  Moves incorporated messages into another folder. This was discussed above.

  nomoveto

  Disables the previous -moveto option.

  truncate[=bool]

  Controls source mailbox truncation. If bool is not given or it is ‘yes’, the mailbox will be truncated after successful processing. If bool is ‘no’, the source mailbox will not be truncated.

mhl

The ‘ignores’ keyword can be used in variable list. In that case, if its value contains more than one component name it must be enclosed in double-quotes, e.g.:

leftadjust,compwidth=9,"ignores=msgid,message-id,received"

The above is equivalent to the following traditional notation:

leftadjust,compwidth=9
ignores=msgid,message-id,received

The ‘MessageName’ component is not yet implemented.

Interactive prompting is not yet implemented.

The following format variables are silently ignored: ‘center’, ‘split’, ‘datefield’.

mhn

• New option New option -compose forces mhn editing mode. This is also the default mode. This differs from the standard mhn, which switches to the editing mode only if no other options were given and the input file name coincides with the value of mhdraft environment variable.
• Show mode (-show) If an appropriate mhn-show-type[/subtype] was not found, GNU mhn prints the decoded message content using moreproc variable. Standard mhn in this case used to print ‘don't know how to display content’ diagnostic.

  The default behaviour is to pipe the content to the standard input of the mhn-show-type[/subtype] command. This is altered to using a temporary file if the command contains %f or %F escapes.

• Store mode (-store) If the Content-Disposition header contains ‘filename=’, and mhn is invoked with -auto switch, it transforms the file name into the absolute notation and uses it only if it lies below the current mhn-storage directory. Standard mhn only requires that the file name do not begin with ‘/’.

  Before saving a message part, GNU mhn checks if the file already exists. If so, it asks whether the user wishes to rewrite it. This behaviour is disabled when -quiet option was given.

mhparam

The -all mode does not display commented out entries.

pick

New command line option -cflags allows to control the type of regular expressions used. The option must occur right before --component pattern or equivalent construct (like -cc, -from, etc.)

The argument to this option is a string of type specifications:

B	Use basic regular expressions
E	Use extended regular expressions
I	Ignore case
C	Case sensitive

Default is ‘EI’.

The flags remain in effect until the next occurrence of -cflags option.

Sample usage:

pick -cflag BC -subject '*a string' 

The date comparison options (-before and -after accept date specifications in a wide variety of formats, e.g.:

pick -after 20030301
pick -after 2003-03-01
pick -after 01-mar-2003
pick -after 2003-mar-01
pick -before '1 year ago'
etc...

prompter

1. Prompter attempts to use GNU Readline library, if it is installed. Consequently, arguments to -erase and -kill option must follow GNU style key sequence notation (see keyseq in GNU Readline Library).

   If prompter is built without readline, it accepts the following character notations:

   \nnnn

   Here, n stands for a single octal digit.

   ^chr

   This notation is translated to the ASCII code ‘chr + 0100’.

2. Component continuation lines are not required to begin with a whitespace. If leading whitespace is not present, prompter will add it automatically.

refile

1. Linking messages between folders goes against the logic of Mailutils, so refile never makes links even if called with -link option. The latter is actually a synonym for -copy, which preserves the original message.
2. The -preserve option is not implemented. It is retained for backward compatibility only.
3. Message specs and folder names may be interspersed.

repl

Understands -use option. Disposition shell provides use command.

rmm

1. Different behaviour if one of the messages in the list does not exist:

   Mailutils rmm does not delete any messages. Standard rmm in this case deletes all messages preceding the non-existent one.

2. The rmm utility will unlink messages, if the rmmproc profile component has empty value, e.g.:

   rmmproc:
   

sortm

New option -numfield specifies numeric comparison for the given field.

Any number of -datefield, -textfield and -numfield options may be given, thus allowing to build sort criteria of arbitrary complexity.

The order of -.*field options sets the ordering priority. This differs from the behaviour of the standard sortm, which always orders datefield-major, textfield-minor.

Apart from sorting the mailfolder the following actions may be specified:

-list

List the ordered messages using a format string given by -form or -format option.

-dry-run

Do not actually sort messages, rather print what would have been done. This is useful for debugging purposes.