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Next: The active file Up: C-News Previous: Installation

The sys file

The sys file, located in /usr/lib/news, controls which hierarchies you receive and forward to other sites. Although there are maintenance tools named addfeed and delfeed, I think it's better to maintain this file by hand.

The sys file contains entries for each site you forward news to, as well as a description of the groups you will accept. An entry looks like 

           site[/exclusions]:grouplist[/distlist][:flags[:cmds]]
Entries may be continued across newlines using a backslash (\). A hash sign (#) denotes a comment.
site
This is the name of the site the entry applies to. One usually chooses the site's UUCP name for this. There has to be an entry for your site in the sys file, too, else you will not receive any articles yourself.

The special site name ME denotes your site. The ME entry defines all groups you are willing to store locally. Articles that aren't matched by the ME line will go to the junk group.

Since C News checks site against the site names in the Path: header field, you have to make sure they really match. Some sites use their fully qualified domain name in this field, or an alias like news.site.domain. To prevent any articles from being returned to these sites, you have to add these to the exclusion list, separated by commas.

For the entry applying to site moria, for instance, the site field would contain moria/moria.orcnet.org.

grouplist
This is a comma-separated subscription list of groups and hierarchies for that particular site. A hierarchy may be specified by giving the hierarchy's prefix (such as comp.os for all groups whose name starts with this prefix), optionally followed by the keyword all (e.g. comp.os.all).

A hierarchy or group is excluded from forwarding by pre- ceding it with an exclamation mark. If a newsgroup is checked against the list, the longest match applies. For example, if grouplist contains 


                     !comp,comp.os.linux,comp.folklore.computers
no groups from the comp hierarchy except comp.folklore.computers and all groups below comp.os.linux will be fed to that site.

If the site requests to be forwarded all news you receive yourself, enter all as grouplist.

distlist
is offset from the grouplist by a slash, and contains a list of distributions to be forwarded. Again, you may exclude certain distributions by preceding them with an exclamation mark. All distributions are denoted by all. Omitting distlist implies a list of all.

For example, you may use a distribution list of all,!local to prevent news for local use only from being sent to remote sites.

There are usually at least two distributions: world, which is often the default distribution used when none is specified by the user, and local. There may be other distributions that apply to a certain region, state, country, etc. Finally, there are two distributions used by C News only; these are sendme and ihave, and are used for the sendme/ihave protocol.

The use of distributions is a subject of debate. For one, some newsreaders create bogus distributions by simply using the top level hierarchy, for example comp when posting to comp.os.linux. Distributions that apply to regions are often questionable, too, because news may travel outside of your region when sent across the Internet.(3) Distributions apply- ing to an organization, however, are very meaningful, for example to prevent confidential information from leaving the company network. This purpose, however, is generally served better by creating a separate newsgroup or hierarchy.

flags
This describes certain parameters for the feed. It may be empty, or a combination of the following:
F
This flag enables batching.
f
This is almost identical to the F flag, but allows C News to calculate the size of outgoing batches more precisely.
I
This flag makes C News produce an article list suitable for use by ihave/sendme. Additional modifi- cations to the sys and the batchparms file are required to enable ihave/sendme.
n
This creates batch files for active NNTP transfer clients like nntpxmit (see chapter 19.). The batch files contain the article's filename along with its message id.
I
This flag makes C News produce an article list suitable for use by ihave/sendme. Additional modifi- cations to the sys and the batchparms file are required to enable ihave/sendme.
n
This creates batch files for active NNTP transfer clients like nntpxmit (see chapter 19.). The batch files contain the article's filename along with its message id.
L
This tells C News to transmit only articles posted at your site. This flag may be followed by a decimal number n, which makes C News only transfer articles posted within n hops from your site. C News deter- mines the number of hops from the Path: field.
u
tells C News to batch only articles from unmod- erated groups.
m
tells C News to batch only articles from moder- ated groups.
You may use at most one of F, f, I, or n.
cmds
This field contains a command to be executed for each article, unless batching is enabled. The article will be fed to the command on standard input. This should only be used for very small feeds; otherwise the load on both systems will be too high.

The default command is 

                     uux - -r -z system!rnews
which invokes rnews on the remote system, feeding it the article on standard input.

The default search path for commands given in this field is /bin:/usr/bin:/usr/lib/news/bin/batch. The latter directory contains a number of shell scripts whose name starts with via; they are briefly described later in this chapter.

If batching is enabled using either of the F or f, I or n flags, C News expects to find a file name in this field rather than a command. If the file name does not begin with a slash (/), it is assumed to be relative to /var/spool/news/out.going. If the field is empty, it defaults to system/togo.

When setting up C-News, you will most probably have to write your own sys file. To help you with it, we give a sample file for vbrew.com below, from which you might copy what you need. 
           # We take whatever they give us.
           ME:all/all::

           # We send everything we receive to moria, except for local and
           # brewery-related articles. We use batching.
           moria/moria.orcnet.org:all,!to,to.moria/all,!local,!brewery:f:

           # We mail comp.risks to jack@ponderosa.uucp
           ponderosa:comp.risks/all::rmail jack@ponderosa.uucp

           # swim gets a minor feed
           swim/swim.twobirds.com:comp.os.linux,rec.humor.oracle/all,!local:f:

           # Log mail map articles for later processing
           usenet-maps:comp.mail.maps/all:F:/var/spool/uumaps/work/batch

Andrew Anderson
Thu Mar 7 23:22:06 EST 1996