expire.ctl - control file for Usenet article expiration
The file <config$_PATH_EXPIRECTL> (typically /var/news/etc/expire.ctl) is
the default control file for the expire(8) program, which reads it at
start-up. Blank lines and lines beginning with a number sign (``#'') are
ignored. All other lines should be in one of two formats.
The first format specifies how long to keep a record of fully-expired
articles. This is useful when a newsfeed intermittently offers older
news that is not kept around very long. (The case of very old news is
handled by the ``-c'' flag of innd(8) .) There should only be one line in
this format, which looks like this:
Where days is a floating-point number that specifies the upper limit to
remember a Message-ID, even if the article has already expired. (It does
not affect article expirations.)
Most of the lines in the file will consist of five colon-separated
fields, as follows:
The pattern field is a list of wildmat(3) -style patterns, separated by
commas. This field specifies the newsgroups to which the line is
applied. Note that the file is interpreted in order, so that the last
line that matches will be used. This means that general patterns (like a
single asterisk to set the defaults) should appear before specific group
The modflag field can be used to further limit newsgroups to which the
line applies, and should be chosen from the following set:
M Only moderated groups
U Only unmoderated groups
A All groups
The next three fields are used to determine how long an article should be
kept. Each field should be either a number of days (fractions like
``8.5'' are allowed) or the word ``never.'' The most common use is to
specify the default value for how long an article should be kept. The
first and third fields -- keep and purge -- specify the boundaries within
which an Expires header will be honored. They are ignored if an article
has no Expires header. The fields are specified in the file as ``lower-
bound default upper-bound,'' and they are explained in this order. Since
most articles do not have explicit expiration dates, however, the second
field tends to be the most important one.
The keep field specifies how many days an article should be kept before
it will be removed. No article in the newsgroup will be removed if it
has been filed for less then keep days, regardless of any expiration
date. If this field is the word ``never'' then an article cannot have
been kept for enough days so it will never be expired.
The default field specifies how long to keep an article if no Expires
header is present. If this field is the word ``never'' then articles
without explicit expiration dates will never be expired.
The purge field specifies the upper bound on how long an article can be
kept. No article will be kept longer then the number of days specified
by this field. All articles will be removed after then have been kept
for purge days. If purge is the word ``never'' then the article will
never be deleted.
It is often useful to honor the expiration headers in articles,
especially those in moderated groups. To do this, set keep to zero,
default to whatever value you wish, and purge to never. To ignore any
Expires header, set all three fields to the same value.
There must be exactly one line with a pattern of ``*'' and a modflags of
``A'' -- this matches all groups and is used to set the expiration
default. It should be the first expiration line.
## How long to keep expired history
## Most things stay for two weeks
## Believe expiration dates in moderated groups, up to six weeks
## Keep local stuff for a long time
Written by Rich $alz <email@example.com> for InterNetNews. This is
revision 1.15, dated 1996/10/29.
expire(8) , wildmat(3) .
You can find a summary and links related to this topic
as part of the Mib Software Usenet RKT.