BUFFCHAN(8)
NAME
buffchan - buffered file-writing backend for InterNetNews
SYNOPSIS
buffchan [ -b ] [ -c lines ] [ -C seconds ] [ -d directory
] [ -f fields ] [ -m map ] [ -p pidfile ] [ -l lines ] [
-L seconds ] [ -r ] [ -s file_format ] [ -u ]
DESCRIPTION
Buffchan reads lines from standard input and copies cer-
tain 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.
OPTIONS
-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 redirec-
tion, 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 news-
feeds(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 speci-
fied 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'' com-
mand.
readmap
The map file (specified with the ``-m'' flag) is
reloaded.
HISTORY
Written by Rich $alz lt;rsalz@uunet.uu.net for InterNet-
News. This is revision 1.11, dated 1996/10/29.
SEE ALSO
ctlinnd(8) filechan(8) innd(8) newsfeeds(5).