buffchan - buffered file-writing backend for InterNetNews
buffchan [ -b ] [ -c lines ] [ -C seconds ] [ -d directory ] [ -f fields ] [ -m map ] [ -p
pidfile ] [ -l lines ] [ -L seconds ] [ -r ] [ -s file_format ] [ -u ]
Buffchan reads lines from standard input and copies certain fields in each line into files
named by other fields within the line. Buffchan is intended to be called by innd(8) as an
-b Once buffchan opens a file it keeps it open. The input must therefore never spec-
ify more files than can the number of available descriptors can keep open. If the
``-b'' flag is used, the program will allocate a buffer and attach it to the file
-c If the ``-c'' flag is used with a number n, then buffchan will close, and re-open,
a file after every n lines are written to a file.
-C Similarly, the ``-C'' flag may be used to specify that all files should be closed
and re-opened every n seconds.
-d The ``-d'' flag may be used to specify a directory the program should change to
before starting. If this flag is used, then the default for the ``-s'' flag is
changed to be a simple ``%s.''
-f Buffchan input is interpreted as a set of lines. Each line contains a fixed number
of initial fields, followed by a variable number of filename fields. All fields in
a line are separated by whitespace. The default number of initial fields is one;
the ``-f'' flag may be used to specify a different number of fields.
-m See filechan(8) for an example.
-p If the ``-p'' flag is used, the program will write a line containing its process ID
(in text) to the specified file.
-l If the ``-l'' flag is used with a number n, then buffchan will call fflush(3) after
every n lines are written to a file.
-L If the ``-L'' flag is used with a number n, then all files will be flushed every n
-r By default, the program sets its standard error to <pathlog in inn.conf>/errlog.
To suppress this redirection, use the ``-r'' flag.
-s After the initial fields, each remaining field names a file to write. The ``-s''
flag may be used to specify a format string that maps the field to a file name.
This is a sprintf(3) format string which should have a single ``%s'' parameter
which will be given the field. The default value is <pathoutgoing in inn.conf>/%s.
See the description of this flag in filechan(8).
-u If the ``-u'' flag is used, the program will request unbuffered output.
Buffchan can be invoked as an exploder feed (see newsfeeds(5)). As such, if a line starts
with an exclamation point it will be treated as a command. There are three commands,
flush The ``flush'' command closes and re-opens all open files; ``flush xxx'' which
flushes only the specified site. These are analogous to the ctlinnd(8) ``flush''
command, and can be achieved by doing a ``send "flush xxx"'' command. Applications
can tell that the ``flush'' has completed by renaming the file before issuing the
command; buffchan has completed the command when the original filename re-appears.
If <$ac_cv_func_fchmod in config.cache> is ``yes'', then buffchan also changes the
access permissions of the file from read-only for everyone to read-write for owner
and group as it flushes or closes each output file. It will change the modes back
to read-only if it re-opens the same file.
drop The ``drop'' command is similar to the ``flush'' command except that any files are
not re-opened. If given an argument, then the specified site is dropped, otherwise
all sites are dropped. (Note that the site will be restarted if the input stream
mentions the site.) When a ctlinnd ``drop site'' command is sent, innd will auto-
matically forward the command to buffchan if the site is a funnel that feeds into
this exploder. To drop all sites, use the ctlinnd ``send buffchan-site drop'' com-
The map file (specified with the ``-m'' flag) is reloaded.
Written by Rich $alz <firstname.lastname@example.org> for InterNetNews. This is revision 220.127.116.11,
ctlinnd(8), filechan(8), inn.conf(5), innd(8), newsfeeds(5).