MH-SEQUENCE(5)
NAME
mh-sequence - sequence specification for nmh message sys-
tem
SYNOPSIS
most nmh commands
DESCRIPTION
A sequence (or sequence set) is a symbolic name represent-
ing 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 several 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 mes-
sage 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 mes-
sage.
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 mes-
sages to a meaningful symbolic name.
The name used to denote a message sequence must consist of
an alphabetic character followed by zero or more alphanu-
meric 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' mes-
sages 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 specificaitions
"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 specifcations 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 ele-
ments 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 "Previ-
ous-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 pro-
grams 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, rcvs-
tore, show, 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 mes-
sages are placed in a folder (using inc or rcvstore), the
new messages will also be added to the sequence(s) named
in the value of this entry. For example, a profile 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 (or next or prev) displays a mes-
sage, 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
CONTEXT
All