is the daemon which is responsible for building and maintaining the
database used by the nn(1) news reader.
is started when the system enters multi-user mode, and runs until
system shutdown. To facilitate this, you should place the following
call in /etc/rc (or similar) to invoke the
$master/nnmaster -l -r -C
where $master is the MASTER_DIRECTORY defined during configuration
is started as specified above, it will first unlock the database in
case it was locked (-l), perform a thorough consistency check on the
Then, every 10 minutes (-r), it will look at the time-stamp
of the news active file to see whether new articles have arrived on
the system (or whether articles have been expired). (See -U)
If the active file has been modified,
will collect the header information from the new articles and enter
them into the database (or remove the headers of the expired articles
from the database).
If it detects that some articles have been expired, it will
automatically remove the header information of the expired articles
from the database.
ARTICLE COLLECTION OPTIONS
Normally, nnmaster will collect all available news groups
defined in the news active file. The set of collected groups can be
controlled via the argument line. Groups can be either included or
A group name, e.g. comp, will cause the group and all its subgroups to
be collected. Individual groups, e.g. news.software.nn, can also be
A group name preceded by an exclamation mark, e.g. !talk.politics,
will cause the group and all its subgroups to be ignored.
An empty argument, i.e. "", will cause all groups that are not ignored
to be collected. For example, to collect everything but rec and misc,
use the following command:
nnmaster -r !rec !misc ""
If the empty argument had been omitted, nothing would be collected,
since the presence of any groups arguments causes nnmaster
to ignore all groups which are not explicitly mentioned.
Example 1: The following commands can be executed by cron to collect
different sets of groups at different intervals or under different
nnmaster -B -O14 rec misc sci -LBO -u
nnmaster !rec !misc !sci "" -u
Example 2: The group arguments are used in the given sequence, e.g. to
leave out comp.sys, but still collect comp.sys.ibm.pc, use the command:
nnmaster -r comp.sys.ibm.pc !comp.sys ""
The use of the -u option in the first example is essential,
since each of the commands will update the active file time stamp
which will prevent the other command from detecting new articles that
Using this method to keep specific groups out of the database must be
used with great caution; just a single invocation of nnmaster
without any arguments will collect all the otherwise ignored groups!
COLLECTION OF ARTICLES
The following options control how nnmaster performs the
collection of new articles.
-r [ min ]
Daemon mode. The nnmaster will put itself in the background
(unless -f is also specified),
and will checks for arrival of new articles and expired articles every
minutes (and update the database accordingly). If
is omitted, the default is to check every 10 minutes.
Without the -r option, the nnmaster will just perform a single
collection of new articles (if any) and then exit. This can be used
to have the nnmaster started by
at regular intervals instead of having it as a daemon which sleeps
between checking for new articles. Since the nnmaster is a bit
expensive to start up (it has to read a few files), it is up to you to
decide which mode is best on your system. (I have also heard that it
works to call nnmaster without -r from
I cannot recommend this unless you receive batched news; invoking
nnmaster for every received article sounds too expensive to me.)
-h [ sec ]
Hold collection of new articles until next scan if new articles have
arrived withing the last sec  seconds. This is useful to
prevent nnmaster from competing for disk i/o with an rnews
process which is unbatching incoming news, or a running expire
process. It will have the side effect of limiting the number of C:
entries in the log, since collection of incoming batches will
typically be done in larger thunks.
Run nnmaster in foreground in daemon mode (see -r).
Useful if nnmaster is invoked from inittab. (Notice that if you
use a respawn entry in inittab, you will not be able to stop
nnmaster using the -k option, since init will immediately
start another master.)
Perform a consistency check on the database on start-up, and rebuild
corrupted database files. This operation can be quite time-consuming
since it reads through all the database files.
Normally, articles without a proper news header (no Newsgroups: line)
are ignored. Specifying the -b option causes these `bad'
articles to be included in the database (normally with no sender or
Remove `bad' articles. Sometimes, articles without a header ends up
in the news spool directory. These articles have no article id, and
therefore, they will never be expired by expire(8). This option
will allow the nnmaster to silently remove these articles (a `B'
entry will occur in the log file).
Ignore articles which are older than the given number of days.
This may help keep old 'stray' articles out of the database. If the
-B options is also specified, the old articles will be removed
from the news spool directories. Old ignored or removed articles will
be reported with an `O' entry in the log file. This option can be
disable for individual groups by the O flag in the GROUPS file
Specifies how the auto-recollect operation is performed on the
groups having this option set in the GROUPS file (see below). Four
methods are available (default is method 1):
1: Run expire on the group when new articles arrive.
2: Run expire on the group on every scan.
3: Recollect all articles when new articles arrive.
4: Recollect all articles on every scan.
Normally, nnmaster will send a message via mail to the news
administrator (OWNER) when an error or potential problems
(primarily nntp related) occur. This can be restricted to only fatal
errors (nnmaster terminated) if mode is 1, and disabled
completely if mode is 0.
Normally, nnmaster will print a message on the system console or
in the syslog if a fatal error happens. This option will prevent
this, so only a type 'E' entry is written to the Log file.
Since articles does not stay forever in the news system, the database
must be cleaned up regularly to remove the information stored for
expired articles. Expiration of the database is normally scheduled
using the nnadmin(1M) command executed by cron at a suitable
time when expire on the news articles has completed. The following
command will send a message to the nnmaster and cause it to
initiate expire on all news groups:
Selective expiration of individual groups can be done from
nnadmin (interactive mode). It can also be done by invoking
nnmaster with the -F option. For example, the following
command will run expire on all groups except the `rec' groups:
nnmaster -F -k !rec ""
The -k option is required to terminate the currently running
master since two daemons cannot be running at the same time. Thus to
run expire (on all groups) in this way from cron, the following
commands must be used:
nnmaster -Fk "" ; nnmaster -r ...
It is also possible to have nnmaster detect expiration
automatically (see -e). This requires that the min field
in the active file is updated by
the news expire (this is not the default case when Cnews is used).
However, this is not always a safe indication since the first article
may not have been expired, while a lot of other articles have been
There are several strategies available in the
nnmaster to do this clean-up, each having their strengths and
Method 1 (default): Rebuilds the database from the existing
database information by comparing the current database contents with
the contents of the news group directories, eliminating entries whose
file no longer exists. This method is guaranteed to eliminate all
expired articles from the database, and it is reasonably fast because
it only has to read the directories, not each article file.
If news is accessed remotely via nntp, the list of existing articles
cannot efficiently be fetched by reading a local directory. Instead
an XHDR request is sent to the nntp server to get a list of articles.
Method 2: Eliminates only the expired articles before the first
article in the group. This is very fast since only the active file
and the database itself is accessed, but it will obviously leave some
expired articles in the database. This method requires that the min
field in the active file is updated by expire.
Method 3: Discard the current database information and
recollects all articles. This is obviously very time consuming, and
it is therefore not recommended, especially not with nntp.
The options related to database expiration are:
Select expire method N. (If N is omitted, the default
method is used).
Automatically run expire in the database on groups where the min
number in the active file has increased by N (1 if omitted) articles.
This is disabled by default (since the min field is often unreliable).
Run expire once and exit. If a list of groups is specified on
the command line, the matched groups (see the rules above) will be
marked for expiration. If no groups are specified, only the groups
already scheduled for expire will be expired. Consequently, to expire
all groups, a blank argument "" (matching all groups) must be specified.
The database can be locked centrally, which will normally disallow all
access to the database, and even block nnmaster from being
(accidentally) started. When a lock is set on the database, all
currently running clients will terminate the next time they try to
access the database. Setting a lock on the database can thus also be
used to force running clients to terminate.
The following options set and clear locks on the database:
Locks the database with the given message. The message will be
displayed every time a program tries to access the database.
Unlock the database if it was locked.
Ignore a possible lock and continue. This can be used to have
nnmaster operate on a database which is blocked from normal user
Since only one nnmaster can operate on the database at any one
time, a running nnmaster daemon must be stopped before a lock
can be set on the database. If neither
is specified with the
option (in both forms), nnmaster will terminate after setting or
clearing the lock.
The following options are used to initialize and update the central
Initialize database. This option will erase an existing database, and
create an empty database containing entries for the currently known
groups. nnmaster will offer you to use an existing GROUPS file
when initializing the database.
The optional limit can be used to put a limit on the number of
articles that will be collected in each group during the first
collection of articles following the database initialization. This is
useful on systems where the 'min' field in the active file is
unreliable or not maintained (Cnews doesn't) to limit the work done to
do the initial collection of news after the initialization of the
database. If news is accessed remotely from an NNTP server, this is
even more important! If limit is omitted, or is zero,
nnmaster will trust the min field and collect all articles in
the range min..last.
Reread the GROUPS file. This option is used to instruct
nnmaster to parse the GROUPS file after it has been edited.
See the section on the GROUPS file below.
The following options controls various details of the nnmaster's
-D [ N ]
Run nnmaster in "debug mode". If N is omitted, or equals 1 or
3, this will produce a compact but still very informative trace of the
collection or expire process directly on the terminal. This is most
useful when doing the first collection of articles after initializing
the database with -I. If N is 2 or 3, a trace of the NNTP
traffic is written to a file nnmaster.log in the TMP directory. This
option disables -r.
Identifies the host which nnmaster is running on as the
nntp-server for its clients, i.e. that it can access the news spool
directory locally without using NNTP. Normally, nnmaster will
detect this by itself by comparing the host name to the contents of
the nntp_server file, so this option should really be superfluous.
In some networked environment, opening an article (shared from another
machine via NFS) may fail for no obvious reason. Using this option,
it is possible to cause
nnmaster to perform retries attempts to open an article
before marking the article as non-existing in the database.
Exclude the specified entry types from the log file. This is normally
used to exclude the 'C'ollecting and e'X'pire entries (-LCXO).
Trace the collection process. This will place a lot of information
into the log file (T: entries).
Normally, nnmaster will just compare the time-stamp on the
active file with a time-stamp saved in the database to see if new
articles have arrived. The -u option forces the nnmaster to
the active file on start-up to see if new articles have arrived.
Some SVR4 systems (and maybe SunOS) have a useful "feature". Writing
files with mmap() may not update the last-changed timestamp on the file.
Since INN uses mmap() for writing the active file, this becomes a problem
The -U option causes nnmaster to unconditionally read the active
file each time the repeat delay (-r) time expires.
Print the release and version identification for nnmaster, and exit.
Wakeup the real nnmaster. Send a signal to the nnmaster
daemon to have it check for new articles immediately.
Kill the already running nnmaster daemon before proceeding with
the operation specified by the other options (or terminate if no other
operation is requested).
THE GROUPS FILE
The primary purpose of the GROUPS file is to store the names of the
news groups represented in the database. Each line in the file
corresponds to an entry in the (binary) MASTER file, and the sequence
of the lines in the GROUPS file must never be changed unless the
database is reinitialized afterwards.
However, the contents of the lines in the GROUPS file can be edited to
control how the nnmaster should handle each individual group.
The format of each line is:
news.group.name [ timestamp ] [ flags ]
The news group name is the name of the group, and must not be changed
in any way. If the group is no longer in the news active file, and
consequently the group does no longer exist, group name can be
replaced by a `@' character which will instruct nnmaster to
ignore this entry without having to rebuild the entire database.
The optional time stamp indicates when the line was added to the
GROUPS file and is used by nn to detect new groups. When the
GROUPS file is built initially from the active file, the time stamps
are omitted which simply means that they are "old".
One or more of the following flags can be added to the GROUPS line to
control nnmaster's handling of the group:
Causes nnmaster to treat all articles in the group as digests,
even when they don't initially look like digests. Articles which are
found not to be digests after all, are still not digested.
Instructs nnmaster to never digest any articles in the group.
Disables the -O option for this group, i.e. all existing
articles will be included in the database (and they will not be
removed if the -B option is specified). This flag should be
set on groups which you never expire, or have a very long expire time!
Causes nnmaster to recollect all available articles in the
group whenever a new article is received. This is said to be useful
is some high-traffic clarinet groups with many cancelled articles.
Instructs nnmaster to append all new articles to the
specified file. This makes it possible to keep specific groups out of
the way of expire. The archive file can be access directly from the
nn client using the goto-group command. The file name
must be a full path name to a file in an existing, writeable directory.
Instructs nnmaster to completely ignore this group - this is
equivalent to setting the group name to `@' as described above.
! or X
Causes nnmaster to ignore the group and not collect the group's
articles in the database.
Comments (starting with `#' and continuing to the end of line) and
empty lines are allow in the GROUPS file, but it is strongly
recommended to keep the changes to the GROUPS file as small as
possible, because of the implicit correspondence with the binary
It is not recommended to edit the GROUPS file while nnmaster is
running because it may add new groups to the file. After editing the
GROUPS file, the command
must be run before restarting the nnmaster to parse and verify
the new GROUPS file.
The nnmaster can access the news articles from a local news
spool directory as well as from an NNTP server. When compiled with
NNTP enabled, nnmaster will compare the name of the NNTP server
and the name of the local host; if they are identical, nnmaster
will bypass NNTP and access the articles directly.
When it has to access the news articles via NNTP, it cannot time-stamp
the active file, so instead it transfers the entire active file from
the NNTP server and compares it with a local copy of the last active
file fetched from the NNTP server. This is not very expensive in
terms of cpu-cycles, disk-load, or net-bandwidth, but to stay on
friendly terms with the NNTP server administrator, you should probably
not use shorter update intervals than the standard 10 minutes.
Setting a much higher update interval than the standard 10 minutes is
not really recommended either, since an update normally implies
fetching a burst of news articles from the NNTP server, so setting the
interval too long may imply that the load on the NNTP server will be
In expire method 1, the use of XHDR just to get a list of existing
articles in a group is definitely a waste of resources on the nntp
server (but still lower than using method 3). Before using
the XHDR request, nnmaster will send a
non-standard "LISTGROUP" request; if the nntp server supports this
request, it should return an OK_HEAD status followed by an (unordered)
list of article numbers (one per line) terminated by a `.' line. The
nntp servers supporting this request will be much less loaded during
The -O option does not work with NNTP. The -B option
will only work with NNTP if the nnmaster is running on the NNTP
The $db, $master, and $news names used below are synonyms for the
DB_DIRECTORY, MASTER_DIRECTORY, and NEWS_LIB_DIRECTORY defined during
$db/MASTERDatabase master index
$db/GROUPSNews group names and flags in MASTER file order
$db/DATA/nnn.[dx]Database files for group number nnn
.../.nn[dx]Database files if located in the group directories
$master/GATEMessage channel from nnadmin to nnmaster
$master/MPIDThe process id of the nnmaster daemon.
$LogThe log file (the location is configuration dependent)
$news/activeExisting articles and groups
/usr/lib/nntp_serverContains the name of the NNTP server.
The MASTER file contains a record for each news group, occurring in
the same sequence as the group names in the GROUPS file. The sequence
also defines the group numbers used to identify the files in the
database's DATA directory.
The GATE file will be created by nnadmin when needed, and
removed by nnmaster when it has read it. Therefore, to send a
message to the nnmaster requires that you are allowed to write
in the $master directory.
The contents of the Log file are described in the nnadmin manual.