Section: Maintenance Commands (8)Updated: Harold TayLocal indexUp
NAME
snfetch - fetch articles.
SYNOPSIS
snfetch
[-r]
[-t timeout]
[-c depth]
group [serial [max]]
DESCRIPTION
snfetch
expects to read NNTP from file descriptor 6, and write NNTP to file
descriptor 7, which descriptors must have already been open.
Articles retrieved are written to descriptor 1.
Each article displayed is separated from the next by a
dot on a line by itself. These articles are NNTP safe, in the sense
that double-dot unquoting is not done, and all lines end in CR-LF.
snfetch
expects to begin it's NNTP speech by giving the GROUP command. The
upstream server's greeting must have already been read some other
way. Likewise, when
snfetch
is done, it will not send a QUIT command.
The output is suitable for feeding to
snstore.
snfetch
always checks the article ID of the prospective article before
retrieving it. If the ID already exists in the ID database, the
article will not be retrieved. Note that this does
not
guarantee that all articles retrieved will be unique.
snfetch
does not guarantee to leave the NNTP conversation in a decent state
(there might be more data to read, but
snfetch
aborted part way).
You will need to be root or own /var/spool/sn in order to run this program.
It is not safe to direct the output of several
snfetches
to the same pipe descriptor, but a file descriptor is all right.
OPTIONS
-t timeout
snfetch
will wait only
timeout
seconds (default 180) for data before giving up, if the server doesn't
respond.
-r
Output in news batch format instead. All articles will take the
#! rnews
form only, even if there is just one article, all lines end in
bare linefeed, and dot-unquoting is performed.
-c depth
Employ a command pipeline of depth
depth.
NNTP command pipelining is not officially sanctioned, so by default
no pipeline is used. However, a pipeline with a
depth
greater than 0 will substantally reduce transaction latency
if
the server accepts it. A respectable value for
depth
might be between 1 and 5.
ARGUMENTS
snfetch
takes the name of a single newsgroup on its command line. If
serial
is given, this is taken to be the first article number on
group
on the server to fetch.
If
max
is specified, this is taken to be the maximum number of articles to
fetch. The first article retrieved may be after
serial
if
max
would be violated. If
max
is not specified, there is no limit.
ENVIRONMENT VARIABLES
SNROOT
If this is set and is not empty, the value is used in place of
/var/spool/sn,
the default news spool directory.
FILES
/var/spool/sn/newsgroup/.serial
If
serial
is not specified, the starting serial number is taken from the file
/var/spool/sn/newsgroup/.serial.
This defaults to
0
if the file can't be read.
/var/spool/sn/newsgroup/.serial.tmp
If
snfetch
exits with success (0), the new
serial
is written into this file.
The original file
/var/spool/sn/newsgroup/.serial
is readonly by
snfetch.
/var/spool/sn/newsgroup/.max
If
max
is not specified on the command line,
max
is read from this file.
If the file cannot be read or does not
exist, there is no limit.
EXIT CODES
snfetch
exits 1 on usage error, 2 on system failure, 3 on protocol error,
4 on read timeout, and 0 on success.