MH-SEQUENCE(5)							     [nmh-1.5]							    MH-SEQUENCE(5)

NAME

       mh-sequence - sequence specification for nmh message system

SYNOPSIS

       most nmh commands

DESCRIPTION

       A  sequence  (or  sequence  set)  is  a symbolic name representing a message or collection of messages.	nmh has several internally defined
       sequences, as well as allowing users to define their own sequences.

   Message Specification and Pre-Defined Message Sequences
       Most nmh commands accept a `msg' or `msgs' specification, where `msg' indicates one message and `msgs' indicates one or more messages.	To
       designate a message, you may use either its number (e.g., 1, 10, 234) or one of these "reserved" message names:

	    Name      Description
	    first     the first message in the folder
	    last      the last message in the folder
	    cur       the most recently accessed message
	    prev      the message numerically preceding "cur"
	    next      the message numerically following "cur"

       In commands that take a `msg' argument, the default is "cur".  As a shorthand, "." is equivalent to "cur".

       For  example:  In  a folder containing five messages numbered 5, 10, 94, 177 and 325, "first" is 5 and "last" is 325.  If "cur" is 94, then
       "prev" is 10 and "next" is 177.

       The word `msgs' indicates that one or more messages may be specified.  Such a specification consists of one message designation or of  sev-
       eral  message  designations  separated  by  spaces.  A message designation consists either of a message name as defined above, or a message
       range.

       A message range is specified as "name1-name2" or "name:n", where `name', `name1' and `name2' are message names, and `n' is an integer.

       The specification "name1-name2" designates all currently existing messages from `name1' to `name2' inclusive.  The "reserved" message  name
       "all" is a shorthand for the message range "first-last".

       The  specification  "name:n"  designates  up to `n' messages.  These messages start with `name' if `name' is a message number or one of the
       reserved names "first" "cur", or "next", The messages end with `name' if `name' is "prev" or "last".  The  interpretation  of  `n'  may	be
       overridden  by preceding `n' with a plus or minus sign; `+n' always means up to `n' messages starting with `name', and `-n' always means up
       to `n' messages ending with `name'.

       In commands which accept a `msgs' argument, the default is either "cur" or "all", depending on which makes more sense for each command (see
       the  individual	man pages for details).  Repeated specifications of the same message have the same effect as a single specification of the
       message.

       There is also a special "reserved" message name "new" which is used by the mhpath command.

   User-Defined Message Sequences
       In addition to the "reserved" (pre-defined) message names given above, nmh supports user-defined sequence  names.   User-defined  sequences
       allow  the nmh user a tremendous amount of power in dealing with groups of messages in the same folder by allowing the user to bind a group
       of messages to a meaningful symbolic name.

       The name used to denote a message sequence must consist of an alphabetic character followed by zero or more  alphanumeric  characters,  and
       can not be one of the "reserved" message names above.  After defining a sequence, it can be used wherever an nmh command expects a `msg' or
       `msgs' argument.

       Some forms of message ranges are allowed with user-defined sequences.  The specification "name:n" may be used, and it designates up to  the
       first `n' messages (or last `n' messages for `-n') which are elements of the user-defined sequence `name'.

       The  specifications  "name:next" and "name:prev" may also be used, and they designate the next or previous message (relative to the current
       message) which is an element of the user-defined sequence `name'.  The  specifications  "name:first"  and  "name:last"  are  equivalent	to
       "name:1"  and  "name:-1", respectively.	The specification "name:cur" is not allowed (use just "cur" instead).  The syntax of these message
       range specifications is subject to change in the future.

       User-defined sequence names are specific to each folder.  They are defined using the pick and mark commands.

   Public and Private User-Defined Sequences
       There are two varieties of user-defined sequences: public and private.  Public sequences of a folder are accessible to any  nmh	user  that
       can  read that folder.  They are kept in each folder in the file determined by the "mh-sequences" profile entry (default is .mh_sequences).
       Private sequences are accessible only to the nmh user that defined those sequences and are kept in the user's nmh context file.

       In general, the commands that create sequences (such as pick and mark) will create public sequences if the folder for which  the  sequences
       are  being defined is writable by the nmh user.	For most commands, this can be overridden by using the switches -public and -private.  But
       if the folder is read-only, or if the "mh-sequences" profile entry is defined but empty, then private sequences will be created instead.

   Sequence Negation
       Nmh provides the ability to select all messages not elements of a user-defined sequence.  To do this, the  user	should	define	the  entry
       "Sequence-Negation"  in	the  nmh  profile file; its value may be any string.  This string is then used to preface an existing user-defined
       sequence name.  This specification then refers to those messages not elements of the specified sequence name.  For example, if the  profile
       entry is:

	    Sequence-Negation: not

       then  anytime an nmh command is given "notfoo" as a `msg' or `msgs' argument, it would substitute all messages that are not elements of the
       sequence "foo".

       Obviously, the user should beware of defining sequences with names that begin with the value of the "Sequence-Negation" profile entry.

   The Previous Sequence
       Nmh provides the ability to remember the `msgs' or `msg' argument last given to an nmh command.	The entry  "Previous-Sequence"	should	be
       defined	in the nmh profile; its value should be a sequence name or multiple sequence names separated by spaces.  If this entry is defined,
       when when an nmh command finishes, it will define the sequence(s) named in the value of this entry to be those messages that were specified
       to the command.	Hence, a profile entry of

	    Previous-Sequence: pseq

       directs any nmh command that accepts a `msg' or `msgs' argument to define the sequence "pseq" as those messages when it finishes.

       Note:  there  can  be  a  performance penalty in using the "Previous-Sequence" facility.  If it is used, all nmh programs have to write the
       sequence information to the .mh_sequences file for the folder each time	they  run.   If  the  "Previous-Sequence"  profile  entry  is  not
       included, only pick and mark will write to the .mh_sequences file.

   The Unseen Sequence
       Finally,  many  users like to indicate which messages have not been previously seen by them.  The commands inc, rcvstore, show, mhshow, and
       flist honor the profile entry "Unseen-Sequence" to support this activity.  This entry in the .mh_profile should be defined as one  or  more
       sequence  names	separated by spaces.  If there is a value for "Unseen-Sequence" in the profile, then whenever new messages are placed in a
       folder (using inc or rcvstore), the new messages will also be added to all the sequences named in this profile entry.  For example, a  pro-
       file entry of

	    Unseen-Sequence: unseen

       directs	inc  to  add new messages to the sequence "unseen".  Unlike the behavior of the "Previous-Sequence" entry in the profile, however,
       the sequence(s) will not be zeroed by inc.

       Similarly, whenever show, mhshow, next, or prev displays a message,  that  message  will  be  removed  from  any  sequences  named  by  the
       "Unseen-Sequence" entry in the profile.

FILES

       $HOME/.mh_profile	  The user profile
       <mh-dir>/context 	  The user context
       <folder>/.mh_sequences	  File for public sequences

PROFILE COMPONENTS

       mh-sequences:	    Name of file to store public sequences
       Sequence-Negation:   To designate messages not in a sequence
       Previous-Sequence:   The last message specification given
       Unseen-Sequence:     Those messages not yet seen by the user

SEE ALSO

       flist(1), mark(1), pick(1), mh-profile(5)

DEFAULTS

       None

MH.6.8								   11 June 2012 						    MH-SEQUENCE(5)