EXPIRE(8) UNIX System V(15 Jan 1991) EXPIRE(8)
NAME
expire, doexpire - expire old news
mkhistory - rebuild news history file
upact - update news active file
recovact - partially recover news active file
SYNOPSIS
/usr/dell/cnews/newsbin/expire/expire [ -a archdir ] [ -p ] [ -s ] [ -F c
] [ -c ] [ -n nnnnn ] [ -t ] [ -l ] [ -v ] [ -d ] [ -r ] [ -g ] [ -h ] [
controlfile ]
/usr/dell/cnews/newsbin/expire/doexpire expireoptions
/usr/dell/cnews/newsbin/expire/mkhistory
/usr/dell/cnews/newsbin/expire/upact
/usr/dell/cnews/newsbin/expire/recovact
DESCRIPTION
Expire expires old news, removing it from the current-news directories
and (if asked to) archiving it elsewhere. It updates news's history file
to match. Expire should normally be run nightly, typically by using
doexpire (see below).
Expire's operations are controlled by a control file (which can be named
or supplied on standard input), which is not optional-there is no default
behavior. Each line of the control file (except for empty lines and
lines starting with `#', which are ignored) should have four white-
space-separated fields, as follows.
The first field is one or more newsgroups, separated by commas (no
spaces!); partial specifications are acceptable (e.g. `comp' specifies
all groups with that prefix).
The second field is one letter, `m', `u', or `x', specifying that the
line applies only to moderated groups, only to unmoderated groups, or to
both, respectively.
The third field specifies the expiry period in days. The most general
form is three numbers separated by dashes. The units are days, decimal
fractions are permitted, and ``never'' is shorthand for an extremely
large number. The first number gives the retention period: how long
must pass after an article's arrival before it is a candidate for expiry.
The third number gives the purge period: how long must pass after
arrival before the article will be expired unconditionally. The middle
number gives the expiry period: how long after an article's arrival it
is expired by default. An explicit expiry date in the article will
override the expiry period but not the retention period or the purge
period. If the field contains only two numbers with a dash separating
them, the retention period defaults to 0. If the field contains only a
number, the retention period defaults to 0 and the purge period defaults
to `never'. (But see below.) The retention period must be less than the
purge period, and the expiry period must lie between them.
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The fourth field is an archiving directory, or `@' which indicates that
the default archiving directory (see -a) should be used, or `-' which
suppresses archiving. An explicit archiving directory (not `@') prefixed
with `=' means that articles should be archived into that directory
itself; normally they go into subdirectories under it by newsgroup name,
as in the current-news directory tree. (E.g., article 123 of
comp.pc.drivel being archived into archive directory /exp would normally
become /exp/comp/pc/drivel/123, but if the archiving directory was given
as `=/exp' rather than `/exp', it would become /exp/123.) Expire creates
subdirectories under an archiving directory automatically, but will not
create the archiving directory itself. Archiving directories must be
given as full pathnames.
The first line of the control file which applies to a given article is
used to control its expiry. It is an error for no line to apply; the
last line should be something like `all x 7 -' to ensure that at least
one line is always applicable. Cross-posted articles are treated as if
they were independently posted to each group.
The retention and purge defaults can be overridden by including a bounds
line, one with the special first field /bounds/. The retention and purge
defaults for following lines will be those of the bounds line. The
defaults ``stretch'' as necessary to ensure that the purge period is
never less than the expiry period and the retention period is never
greater than the expiry period. The other fields of a bounds line are
ignored but must be present.
Entries in the history file can be retained after article expiry, to stop
a late-arriving copy of the article from being taken as a new article.
To arrange this, include a line with the special first field /expired/;
this line then controls the expiry of history lines after the
corresponding articles expire. Dates are still measured from article
arrival, not expiry. The other fields of such a line are ignored but
must be present. It is strongly recommended that such a line be
included, and that it specify as long a time as practical.
Command-line options are:
-a dir dir is the default archiving directory; if no default is given,
the control file may not contain any `@' archive-directory
fields.
-p print an `index' line for each archived article, containing its
pathname, message ID, date received, and `Subject:' line.
-s space is tight; optimize error recovery to minimize space
consumed rather than to leave as much evidence as possible.
-F c the subfield separator character in the middle history field is
c rather than the normal `~'.
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-c check the format and consistency of the control file and the
active file, but do not do any expiring.
-n nnnnn set expire's idea of the time to nnnnn (for testing).
-t print (on standard error) a shell-script-like description of
what would be done, but don't do it. In the absence of
archiving, all output lines will be of the form
``remove name'', where name is a pathname relative to
/var/spool/news. If an article is to be archived, this will be
preceded (on the same line) by ``copy name dir ; '', where name
is as in remove and dir is an archiving directory (including
any `=' prefix) as specified by the control file or the -a
option.
-l consider first filename in a history line to be the leader of
its line, to be expired only after all others have expired.
(Meant for use on obnoxious systems like VMS which don't
support real links.)
-r suppress history rebuild. Mostly for emergencies. (This
leaves the history file out of date and larger than necessary,
but improves speed and eliminates the need for several
megabytes of temporary storage.)
-h do not expire any article which would be archived if it were
expired. Mostly for emergencies, so that expire can be run (to
delete articles in non-archived groups) even if space is short
in archiving areas.
-v verbose: report some statistics after termination.
-g report expiry dates that getdate(3) does not like. Expire
ignores such dates, treating the article as if it had no
explicit expiry date.
-d turn on (voluminous and cryptic) debugging output.
Expire considers the middle field of a history line to consist of one or
more subfields separated by `~'. The first is the arrival date, which
can be either a getdate(3)-readable date or a decimal seconds count;
expire leaves this field unchanged. The second-if present, non-null, and
not `-'-is an explicit expiry date for the file, again in either format,
which expire will convert to a decimal seconds count as it regenerates
the history file. Subsequent fields are preserved but ignored.
Doexpire checks whether another doexpire is running, checks that there is
enough disk space, invokes expire with any expireoptions given and with
/usr/dell/cnews/lib/explist as the control file, and reports any
difficulties by sending mail to usenet. This is usually better than just
running expire directly. If space is not adequate for archiving,
doexpire reports this and invokes expire with the -h option. If -r is
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not among the expireoptions, and disk space is persistently inadequate
for the temporaries needed for history rebuilding, doexpire reports this
and invokes expire with the -r option anyway.
Mkhistory rebuilds the history file and its auxiliaries to match the
articles in /var/spool/news. Upact updates the third fields of the
active file to match the articles in /var/spool/news (for historical
reasons, expire does not do this). Recovact updates the second fields of
the active file to match the articles in /var/spool/news, for use in
disaster recovery based on an outdated active file. These programs are
all fairly slow and they all lock the whole news system for the duration
of the run, so they should not be run casually.
FILES
/usr/dell/cnews/lib/historyhistory file
/usr/dell/cnews/lib/history.pagdbm database for history file
/usr/dell/cnews/lib/history.dirdbm database for history file
/usr/dell/cnews/lib/explistexpiry control file
/usr/dell/cnews/lib/history.ohistory file as of last expiry
/usr/dell/cnews/lib/history.n*new history file and dbm files abuilding
/usr/dell/cnews/lib/LOCKexpiredoexpire's lock file
/usr/dell/cnews/newsbin/expire/*various auxiliaries
SEE ALSO
inews(1), dbm(3), relaynews(8)
HISTORY
Written at U of Toronto by Henry Spencer, with contributions by Geoff
Collyer.
BUGS
Archiving is always done by copying, never by linking. This has the side
effect that cross-posted articles are archived as several independent
copies.
The -p subject-finder botches continued header lines, as does mkhistory,
although such lines are rare.
Upact is a distasteful kludge, but then, so is the third field of the
active file.
Upact forces the third field of the active file to be at least five
digits, for backward compatibility, but otherwise just makes it as large
as necessary. The group-creation operations always create it ten digits
long. The discrepancy is harmless, since unlike the second field, the
third field is never updated in place.
One cannot put more than one newsgroup into a single archiving directory
with the `=' feature, since the article numbers will collide with each
other and expire doesn't do anything about this. Note that archiving a
newsgroup which has subgroups into an `=' directory puts all the
subgroups in the same directory as the parent! (Specifying the group as
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`foo.bar,!foo.bar.all' will avoid this.)
Mkhistory is inherently incapable of reconstructing history-file lines
corresponding to expired articles. Protection against old articles
reappearing is thus somewhat limited for a while after the history file
is rebuilt.
Expire uses access(2) to test for the presence of archiving directories,
which can cause anomalies if it is run setuid (normally it's not).
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