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 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. 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 seconds.
- -r
- By default, the program sets its standard error to
/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 /var/spool/news/out.going/%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, described below:
- 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.
- 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.
- readmap
- The map file (specified with the ``-m'' flag) is reloaded.
Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews.
This is revision 1.11, dated 1996/10/29.