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From: ken@rochester.UUCP
Newsgroups: comp.unix.questions,comp.unix.wizards
Subject: Re: Filters for the BSD print spooling system
Message-ID: <26513@rochester.ARPA>
Date: Mon, 30-Mar-87 16:30:57 EST
Article-I.D.: rocheste.26513
Posted: Mon Mar 30 16:30:57 1987
Date-Received: Wed, 1-Apr-87 01:41:58 EST
References: <111@coke.UUCP>
Reply-To: ken@rochester.UUCP (Ken Yap)
Organization: U of Rochester, CS Dept, Rochester, NY
Lines: 36
Keywords: sun bsd print spooler printer filter
Xref: utgpu comp.unix.questions:1555 comp.unix.wizards:1601

I don't know what your specific problem is but here are some things I
discovered while writing lpd filters myself.

Pay attention to the environment of the filter when it is run.  One way
of debugging is to do "su - daemon" to get the enviroment of the
daemon. You will find that only a few directories are on the path. I
personally use absolute pathnames for any commands run in the filter.

I prefer to use sh for filters (and shell programming in general).
Faster and less hassles. I put this line near the top of the filter
script:

	trap "rm -f TEMPFILES" 0 1 2 3 15

Check that the permissions of any files (e.g. logfiles) that need to be
written on are correct for group daemon.

Another thing I discovered only by looking through the lpr code is that
the -d, -n and -t flags imply -l, and the last flag specified
supercedes the previous ones, so don't type "lpr -d -l foo.dvi" because
the job will be queued with the l flag (print raw).

Here is an example of our dvi to press filter running here:

#! /bin/sh
statusfile=/usr/spool/raven/status
trap "/bin/rm -f /tmp/$$.dvi /tmp/$$.press" 0 1 2 3 15
umask 077
/bin/cat > /tmp/$$.dvi
/bin/echo "Converting dvi to Press" > $statusfile
2>&1 /usr/staff/bin/dvip -p /tmp/$$.press /tmp/$$.dvi > /dev/null
/bin/echo "Sending Press file to Raven" > $statusfile
/usr/lib/xpressf < /tmp/$$.press
exit 0

	Ken