buffchan.8

早期freebsd实现

.\" $Revision: 1.7 $
.TH BUFFCHAN 8
.SH NAME
buffchan \- buffered file-writing backend for InterNetNews
.SH SYNOPSIS
.B buffchan
[
.B \-b
]
[
.BI \-c " lines"
]
[
.BI \-C " seconds"
]
[
.BI \-d " directory"
]
[
.BI \-f " fields"
]
[
.BI \-m " map"
]
[
.BI \-p " pidfile"
]
[
.BI \-l " lines"
]
[
.BI \-L " seconds"
]
[
.B \-r
]
[
.BI \-s " file_format"
]
[
.B \-u
]
.SH DESCRIPTION
.I Buffchan
reads lines from standard input and copies certain fields in
each line into files named by other fields within the line.
.I Buffchan
is intended to be called by
.IR innd (8)
as an exploder feed.
.PP
.I 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
.IR filechan (8)
for an example.
.PP
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
.IR sprintf (3)
format string which should have a single ``%s'' parameter which will be given
the field.
The default value is
.\" =()<.IR @<_PATH_BATCHDIR>@/ %s.>()=
.IR /var/spool/news/out.going/ %s.
See the description of this flag in
.IR filechan (8).
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.''
.PP
Once
.I 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
.IR setbuf (3).
If the ``\-u'' flag is used, the program will request unbuffered output.
.PP
If the ``\-l'' flag is used with a number
.IR n ,
then
.I buffchan
will call
.IR fflush (3)
after every
.I n
lines are written to a file.
If the ``\-c'' flag is used with a number
.IR n ,
then
.I buffchan
will close, and re-open, a file after every
.I n
lines are written to a file.
.PP
If the ``\-L'' flag is used with a number
.IR n ,
then all files will be flushed every
.I n
seconds.
Similarly, the ``\-C'' flag may be used to specify that all files should
be closed and re-opened every
.I n
seconds.
.PP
By default, the program sets its standard error to
.\" =()<.IR @<_PATH_ERRLOG>@ .>()=
.IR /var/spool/news/data/errlog .
To suppress this redirection, use the ``\-r'' flag.
.PP
If the ``\-p'' flag is used, the program will write a line containing
its process ID (in text) to the specified file.
.PP
.I Buffchan
can be invoked as an exploder feed (see
.IR 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:
.TP
.B flush
The ``flush'' command closes and re-opens
all open files; ``flush\ xxx'' which flushes only the specified site.
These are analogous to the
.IR 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;
.I buffchan
has completed the command when the original filename re-appears.
.\" =()<.if '@<HAVE_FCHMOD>@'DO' \{\>()=
.if 'DO'DO' \{\
.PP
.I 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.\}
.PP
.B 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
.I ctlinnd
\&``drop site'' command is sent,
.I innd
will automatically forward the command to
.I buffchan
if the site is a funnel that feeds into this exploder.
To drop all sites, use the
.I ctlinnd
\&``send buffchan-site drop'' command.
.TP
.B readmap
The map file (specified with the ``\-m'' flag) is reloaded.
.SH HISTORY
Written by Rich $alz <[e-mail]> for InterNetNews.
.de R$
This is revision \\$3, dated \\$4.
..
.R$ $Id: buffchan.8,v 1.7 1993/03/18 21:03:33 rsalz Exp $
.SH "SEE ALSO"
ctlinnd(8),
filechan(8),
innd(8),
newsfeeds(5).