alternative batchers may be provided. For instance, the ihave/sendme protocol requires the article list to be turned into ihave or sendme control messages, which are posted to the newsgroup to.site. This is performed by batchih and batchsm.
muncher
The muncher field specifies the compression command. Usually, this is compcun, a script that produces a compressed batch.[128] Alternatively, suppose you create a muncher that uses gzip, say gzipcun (note that you have to write it yourself). You have to make sure that uncompress on the remote site is patched to recognize files compressed with gzip.
If the remote site does not have an uncompress command, you may specify nocomp, which does not do any compression.
transport
The last field, transport, describes the transport to be used. A number of standard commands for different transports are available; their names begin with via. sendbatches passes them the destination sitename on the command line. If the batchparms entry is not /default/, sendbatches derives the sitename from the site field by stripping it of anything after and including the first dot or slash. If the batchparms entry is /default/, the directory names in out.going are used.
To perform batching for a specific site, use the following command:
# su news -c '/usr/lib/news/batch/sendbatches site'
When invoked without arguments, sendbatches handles all batch queues. The interpretation of 'all' depends on the presence of a default entry in batchparms. If one is found, all directories in /var/spool/news/out.going are checked; otherwise, sendbatches cycles through all entries in batchparms, processing just the sites found there. Note that sendbatches, when scanning the out.going directory, takes only those directories that contain no dots or at signs (@) as sitenames.
There are two commands that use uux to execute rnews on the remote system: viauux and viauuxz. The latter sets the -z flag for uux to keep older versions from returning success messages for each article delivered. Another command, viamail, sends article batches to the user rnews on the remote system via mail. Of course, this requires that the remote system somehow feeds all mail for rnews to its local news system. For a complete list of these transports, refer to the newsbatch manual page.
All commands from the last three fields must be located in either out.going/site or /usr/lib/news/batch. Most of them are scripts; you can easily tailor new tools for your personal needs. They are invoked through pipes. The list of articles is fed to the batcher on standard input, which produces the batch on standard output. This is piped into the muncher, and so on.
Here is a sample file:
# batchparms file for the brewery
# site | size |max |batcher |muncher |transport
#-------------+--------+-------+---------+-----------+-----------
/default/ 100000 22 batcher compcun viauux
swim 10000 10 batcher nocomp viauux
In B News, expiration needs to be performed by a program called expire, which took a list of newsgroups as arguments, along with a time specification after which articles had to be expired. To have different hierarchies expire at different times, you had to write a script that invoked expire for each of them separately. C News offers a more convenient solution. In a file called explist, you may specify newsgroups and expiration intervals. A command called doexpire is usually run once a day from cron and processes all groups according to this list.
Occasionally, you may want to retain articles from certain groups even after they have been expired; for example, you might want to keep programs posted to comp.sources.unix. This is called archiving. explist permits you to mark groups for archiving.
An entry in explist looks like this:
grouplist perm times archive
grouplist is a comma-separated list of newsgroups to which the entry applies. Hierarchies may be specified by giving the group name prefix, optionally appended with all. For example, for an entry applying to all groups below comp.os, enter either comp.os or comp.os.all.
When expiring news from a group, the name is checked against all entries in explist in the order given. The first matching entry applies. For example, to throw away the majority of comp after four days, except for comp.os.linux.announce, which you want to keep for a week, you simply have an entry for the latter, which specifies a seven-day expiration period, followed by an expiration period for comp, which specifies four days.
The perm field details if the entry applies to moderated, unmoderated, or any groups. It may take the values m, u, or x, which denote moderated, unmoderated, or any type.
The third field, times, usually contains only a single number. This is the number of days after which articles expire if they haven't been assigned an artificial expiration date in an Expires: field in the article header. Note that this is the number of days counting from its arrival at your site, not the date of posting.
The times field may, however, be more complex than that. It may be a combination of up to three numbers separated from one another by dashes. The first denotes the number of days that have to pass before the article is considered a candidate for expiration, even if the Expires: field would have it expire already. It is rarely useful to use a value other than zero. The second field is the previously mentioned default number of days after which it will be expired. The third is the number of days after which an article will be expired unconditionally, regardless of whether it has an Expires: field or not. If only the middle number is given, the other two take default values. These may be specified using the special entry /bounds/, which is described a little later.
The fourth field, archive, denotes whether the newsgroup is to be archived and where. If no archiving is intended, a dash should be used. Otherwise, you either use a full pathname (pointing to a directory) or an at sign (@). The at sign denotes the default archive directory, which must then be given to doexpire by using the -a flag on the command line. An archive directory should be owned by news. When doexpire archives an article from say, comp.sources.unix, it stores it in the directory comp/sources/unix below the archive directory, creating it if necessary. The archive directory itself, however, will not be created.
There are two special entries in your explist file that doexpire relies on. Instead of a list of newsgroups, they have the keywords /bounds/ and /expired/. The /bounds/ entry contains the default values for the three values of the times field described previously.
The /expired/ field determines how long C News will hold onto lines in the history file. C News will not remove a line from the history file once the corresponding article(s) have been expired, but will hold onto it in case a duplicate should arrive after this date. If you are fed by only one site, you can keep this value small. Otherwise, a couple of weeks is advisable on UUCP networks, depending on the delays you experience with articles from these sites.
