pick.rf

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\"	@(MHWARNING)
.\" @(#)$Id: pick.rf,v 1.1 90/07/20 09:42:04 sharpe Exp Locker: sharpe $
.SC PICK 1
.NA
pick \- select messages by content
.SY
.ie t \{\
.ta .4i 1.8i
.nf
.in .5i
^pick~^^\0\-cc~^ \%[+folder] \%[msgs] \%[\-help]
^^^\0\-date~^ \%[\-before\ date] \%[\-after\ date] \%[\-datefield\ field]
^^^\0\-from~^
^^^\s+2\b'\(lt\(bv\(bv\(lk\(bv\(bv\(lb'\s0\-search~\s+2\b'\(rt\(bv\(bv\(rk\(bv\(bv\(rb'\s0^ pattern \%[\-and\ ...] \%[\-or\ ...] \%[\-not\ ...] \%[\-lbrace\ ...\ \-rbrace]
^^^\0\-subject~^
^^^\0\-to~^ \%[\-sequence\ name\ ...] \%[\-public] \%[\-nopublic] \%[\-zero] \%[\-nozero]
^^^\0\-\|\-component~^ \%[\-list] \%[\-nolist]
.fi
.re
.in 1i
.\}
.el \{\
.ti .5i
pick
\%[+folder] \%[msgs]
\%[\-and\ ...] \%[\-or\ ...] \%[\-not\ ...] \%[\-lbrace\ ...\ \-rbrace]
\%[\-\|\-component\ pattern]
\%[\-after\ date] \%[\-before\ date] \%[\-datefield\ field]
\%[\-sequence\ name\ ...]
\%[\-public] \%[\-nopublic]
\%[\-zero] \%[\-nozero]
\%[\-list] \%[\-nolist]
\%[\-help]
.\}

.ti .5i
typically:
.br
scan\0`pick\0\-from\0jones`
.br
pick\0\-to\0holloway\0\-sequence\0select
.br
show\0`pick\0\-before\0friday`
.DE
\fIPick\fR searches messages within a folder for the specified
contents, and then identifies those messages.
Two types of search primitives are available:
pattern matching and date constraint operations.

A modified \fIgrep\fR(1) is used to perform the matching, so the
full regular expression (see \fIed\fR(1)) facility is available
within `pattern'.
With `\-search', `pattern' is used directly,
and with the others, the grep pattern constructed is:

.ti +.5i
\*(lqcomponent[ \\t]*:\&.*pattern\*(rq

This means that the pattern specified for a `\-search' will be
found everywhere in the message, including the header and the body,
while the other pattern matching requests are limited to the single
specified component.
The expression

.ti +.5i
`\-\|\-component\ pattern'

is a shorthand for specifying

.ti +.5i
`\-search \*(lqcomponent[ \\t]*:\&.*pattern\*(rq\ '

It is used to pick a component which is not one of
\*(lqTo:\*(rq, \*(lqcc:\*(rq, \*(lqDate:\*(rq, \*(lqFrom:\*(rq,
or \*(lqSubject:\*(rq.
An example is `pick\0\-\|\-reply\-to\0pooh'.

Pattern matching is performed on a per\-line basis.
Within the header of
the message, each component is treated as one long line, but in
the body, each line is separate.
Lower\-case letters in the
search pattern will match either lower or upper case in the
message, while upper case will match only upper case.

Independent of any pattern matching operations requested,
the switches `\-after date' or `\-before date' may also be used
to introduce date/time contraints on all of the messages.
By default, the \*(lqDate:\*(rq field is consulted,
but if another date yielding field
(such as \*(lqBB\-Posted:\*(rq or \*(lqDelivery\-Date:\*(rq) should be used,
the `\-datefield\ field' switch may be used.
\fIPick\fR will actually parse the date fields in each of the messages
specified in `msgs'
(unlike the `\-date' switch described above which does a pattern matching
operation),
and compare them to the date/time specified by use of the `\-after'
and `\-before' switches.
If `\-after' is given,
then only those messages whose \*(lqDate:\*(rq field value
is chronologically after
the date specified will be considered.
The `\-before' switch specifies the complimentary action.

Both the `\-after' and `\-before' switches take legal 822\-style date
specifications as arguments.
\fIPick\fR will default certain missing fields so that the entire date
need not be specified.
These fields are (in order of defaulting):
timezone, time and timezone, date, date and timezone.
All defaults are taken from the current date, time, and timezone.
In addition to 822\-style dates,
\fIpick\fR will also recognize any of the days of the week
(\*(lqsunday\*(rq, \*(lqmonday\*(rq, and so on),
and the special dates
\*(lqtoday\*(rq, \*(lqyesterday\*(rq, and \*(lqtomorrow\*(rq.
All days of the week are judged to refer to a day in the past
(e.g., telling \fIpick\fR \*(lqsaturday\*(rq on
a \*(lqtuesday\*(rq means \*(lqlast\ saturday\*(rq
not \*(lqthis\ saturday\*(rq).
Finally, in addition to these special specifications,
\fIpick\fR will also honor a specification of the form \*(lq\-dd\*(rq,
which means \*(lqdd days ago\*(rq.

\fIPick\fR supports complex boolean operations on the searching primitives
with the `\-and', `\-or', `\-not', and `\-lbrace\ ...\ \-rbrace' switches.
For example,

.ti +.5i
pick\0\-after\0yesterday\0\-and\0\-lbrace\0\-from\0freida\0\-or\0\-from\0fear\0\-rbrace

identifies messages recently sent by \*(lqfrieda\*(rq or \*(lqfear\*(rq.

The matching primitives take precedence over the `\-not' switch,
which in turn takes precedence over `\-and'
which in turn takes precedence over `\-or'.
To override the default precedence,
the `\-lbrace' and `\-rbrace' switches are provided,
which act just like opening and closing parentheses in logical expressions.

Once the search has been performed,
if the `\-list' switch is given,
the message numbers of the selected messages are written to the standard
output separated by newlines.
This is \fIextremely\fR useful for quickly generating arguments for other
\fIMH\fR programs by using the \*(lqbackquoting\*(rq syntax of the shell.
For example,
the command

.ti +.5i
scan\0`pick\0+todo\0\-after\0\*(lq31 Mar 83 0123 PST\*(rq`

says to \fIscan\fR those messages in the indicated folder which meet the
appropriate criterion.
Note that since \fIpick\fR\0's context changes are written out prior to
\fIscan\fR\0's invocation,
you need not give the folder argument to \fIscan\fR as well.

Regardless of the operation of the `\-list' switch,
the `\-sequence name' switch may be given once for each sequence the user
wishes to define.
For each sequence named,
that sequence will be defined to mean exactly those messages selected by
\fIpick\fR.
For example,

.ti +.5i
pick\0\-from\0frated\0\-seq\0fred

defines a new message sequence for the current folder called \*(lqfred\*(rq
which contains exactly those messages that were selected.

Note that whenever \fIpick\fR processes a `\-sequence\ name' switch,
it sets `\-nolist'.

By default, \fIpick\fR will zero the sequence before adding it.
This action can be disabled with the `\-nozero' switch,
which means that the messages selected by \fIpick\fR will be added to the
sequence, if it already exists, and any messages already a part of that
sequence will remain so.

The `\-public' and `\-nopublic' switches are used by \fIpick\fR in the same
way \fImark\fR uses them.
.Fi
^$HOME/\&.mh\(ruprofile~^The user profile
.Pr
^Path:~^To determine the user's MH directory
.Ps
^Current\-Folder:~^To find the default current folder
.Sa
mark(1)
.De
`+folder' defaults to the current folder
.Ds
`msgs' defaults to all
.Ds
`\-datefield date'
.Ds
`\-nopublic' if the folder is read\-only, `\-public' otherwise
.Ds
`\-zero'
.Ds
`\-list' is the default if no `\-sequence', `\-nolist' otherwise
.Co
If a folder is given, it will become the current folder.
.Hi
In previous versions of \fIMH\fR,
the \fIpick\fR command would \fIshow\fR, \fIscan\fR, or \fIrefile\fR the
selected messages.
This was rather \*(lqinverted logic\*(rq from the UNIX point of view,
so \fIpick\fR was changed to define sequences and output those sequences.
Hence, \fIpick\fR can be used to generate the arguments for all other
\fIMH\fR commands,
instead of giving \fIpick\fR endless switches for invoking those commands
itself.

Also, previous versions of \fIpick\fR balked if you didn't specify a search
string or a date/time constraint.
The current version does not, and merely matches the messages you specify.
This lets you type something like:

.ti +.5i
show\0`pick\0last:20\0\-seq\0fear`

instead of typing

.in +.5i
.nf
mark\0\-add\0\-nozero\0\-seq\0fear\0last:20
show\0fear
.fi
.in -.5i

Finally,
timezones used to be ignored when comparing dates:
they aren't any more.
.Bu
The argument to the `\-after' and `\-before' switches must be interpreted
as a single token by the shell that invokes \fIpick\fR.
Therefore,
one must usually place the argument to this switch inside double\-quotes.
Furthermore,
any occurance of `\-datefield' must occur prior to the `\-after'
or `\-before' switch it applies to.

If \fIpick\fR is used in a back\-quoted operation,
such as

.ti +.5i
scan\0`pick\0\-from\0jones`

and \fIpick\fR fails (e.g., no messages are from \*(lqjones\*(rq),
then the shell will still run the outer command (e.g., \*(lqscan\*(rq).
Since no messages were matched,
\fIpick\fR produced no output,
and the argument given to the outer command as a result of backquoting
\fIpick\fR is empty.
In the case of \fIMH\fR programs,
the outer command now acts as if the default `msg' or `msgs' should be used
(e.g., \*(lqall\*(rq in the case of \fIscan\fR\0).
To prevent this unexpected behavior,
if `\-list' was given,
and if its standard output is not a tty,
then \fIpick\fR outputs the illegal message number \*(lq0\*(rq when it fails.
This lets the outer command fail gracefully as well.
.En