Provided by: mmh_0.4-2_amd64 
NAME
mh-sequence - sequence specification for mh message system
DESCRIPTION
A sequence (or sequence set) is a symbolic name representing a message or collection of messages. mmh
has several internally defined sequences, as well as allowing users to define their own sequences.
Message Specification and Pre-Defined Message Sequences
Most mmh 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
f the first message in the folder
p the message numerically preceding `c'
c the most recently accessed message
n the message numerically following `c'
l the last message in the folder
In commands that take a `msg' argument, the default is `c'.
For example: In a folder containing five messages numbered 5, 10, 94, 177 and 325, `f' is 5 and `l' is
325. If `c' is 94, then `p' is 10 and `n' 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:i', where `name', `name1' and `name2' are message
names, and `i' is an integer.
The specification `name1-name2' designates all currently existing messages from `name1' to `name2'
inclusive. The `reserved' message name `a' (``all'') is a shorthand for the message range `f-l'.
Name Description
a all messages in the folder (i.e. `f-l')
The specification `name:i' designates up to `i' messages. These messages start with `name' if `name' is
a message number or one of the reserved names `f' `c', or `n', The messages end with `name' if `name' is
`p' or `l'. The interpretation of `i' may be overridden by preceding `i' with a plus or minus sign; `+i'
always means up to `i' messages starting with `name', and `-i' always means up to `i' messages ending
with `name'.
In commands which accept a `msgs' argument, the default is either `c' or `a', 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 `b' (``beyond'') which can be used with the mhpath
command. It refers to the next (not yet used) message number after `l'.
Name Description
b the next message number beyond `l'
User-Defined Message Sequences
In addition to the `reserved' (pre-defined) message names given above, mmh supports user-defined sequence
names. User-defined sequences allow the mmh 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 mmh command expects a `msg' or `msgs' argument.
Some forms of message ranges are allowed with user-defined sequences. The specification `name:i' may be
used, and it designates up to the first `i' messages (or last `i' messages for `-i') which are elements
of the user-defined sequence `name'.
The specifications `name:n' and `name:p' 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:f' and `name:l' are equivalent to `name:1' and `name:-1', respectively. The
specification `name:c' is not allowed (use just `c' instead). Note: 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 mmh 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 mmh user that defined those sequences and are kept in the user's mh 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 mmh 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
Mmh provides the ability to select all messages not elements of a user-defined sequence. A special
string is used to preface an existing user-defined sequence name. This specification then refers to
those messages not elements of the specified sequence name. The default negation prefix is the
exlamation mark `!', but it may be change to any string, by defining the entry `Sequence-Negation' in the
mmh profile file. For example, if the profile entry is:
Sequence-Negation: not
then anytime an mmh 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 default value `!' was chosen due to its similar meaning in the C
programming language, and because it cannot be part of a user-defined sequence. But if your shell
provides history expansion, you might need to quote the exlamation mark (prefix it with a backslash).
To deactivate the negation mechanism, define Sequence-Negation in your profile to an empty value.
The Previous Sequence
Mmh provides the ability to remember the `msgs' or `msg' argument last given to an mmh command. The
entry `Previous-Sequence' should be defined in the mmh profile; its value should be a sequence name or
multiple sequence names separated by spaces. If this entry is defined, when an mmh 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 mmh 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
mmh 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, the unseen sequence indicates which messages have not been previously seen by the user. The
commands inc, rcvstore, show, and flist honor the sequence. Whenever new messages are placed in a folder
(using inc or rcvstore), the new messages will also be added to the unseen sequence.
inc, for example, adds new messages to the unseen sequence. Unlike the behavior of the previous
sequence, however, the unseen sequence will not be zeroed by inc.
Similarly, whenever show, next, or prev display a message, that message will be removed from the unseen
sequence.
The default unseen sequence is named `u'. To change, define a `Unseen-Sequence' entry in your profile.
It may also contain multiple sequence names, separated by spaces. In this case, anything that applied to
a single unseen sequence, applies to multiple ones, too.
The unseen sequence mechanism is automatically activated. To deactivate it, define the `Unseen-Sequence'
entry in your profile with an empty value.
FILES
$HOME/.mmh/profile The user profile
$HOME/.mmh/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