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 exploder feed.
-b Once buffchan opens a file it keeps it open. The input must
therefore never specify 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 using setbuf(3).
-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
-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. See filechan(8) for
-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 seconds.
-r By default, the program sets its standard error to
<config$_PATH_ERRLOG>. (typically /var/log/news/errlog.)
To suppress this redirection, use the ``-r'' flag.
-s After the initial fields, each remaining field names a file to
write. The ``-s'' flag may be used to specify a format string that
maps the field to a file name. This is a sprintf(3) format string
which should have a single ``%s'' parameter which will be given the
field. The default value is <config$_PATH_BATCHDIR>/%s (typically
/var/news/spool/out.going/%s.) See the description of this flag in
-u If the ``-u'' flag is used, the program will request unbuffered
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, described below:
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<config$HAVE_FCHMOD> == DO, 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
automatically 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'' command.
The map file (specified with the ``-m'' flag) is reloaded.
Written by Rich $alz <firstname.lastname@example.org> for InterNetNews. This is
revision 1.11, dated 1996/10/29.
ctlinnd(8) , filechan(8) , innd(8) , newsfeeds(5) .
You can find a summary and links related to this topic
as part of the Mib Software Usenet RKT.