Printers Cheat Sheet - May 1998
Basics...
We mostly use the standard lp printing software (System 5) on our computers, but one computer, the print server, must also have the BSD lpr software set up on it too. This system works as follows:
lp on machine A./var/spool/lp/interface/<printer_name> which sends request
to print server machine and printer_name specified in script./var/spool/lp/interface/<printer_name>, which converts the
file to PostScript format, then issues an lpr command to send the
converted file to the printer. lpr prints the file.Of course, the above scenario is only if everything is working. If you are reading this, something has probably screwed up. The troubleshooting section of this document, attempts to guide you through this process, looking for problems along the way.
The lp parts of this process doesn't seem that complicated. There is a
deamon out there that sits and waits for someone to type in lp
something. When it finds that someone has done that, it runs the script
in the interface directory. The majority of these scripts are just a copy of
the netface script that SGI supplies in the models directory. On the
print server machine(s), this is a script that TJ modified a long time ago. I
think it originally started out as one of the standard things in the
models directory, but SGI changes those a little bit with every release.
The lpr stuff is harder to understand. One of the SysAdmin books that I once read proclaimed "lpr to be the flakiest program within UNIX". The /etc/printcap file is the starting point for this system. The basic idea is that you put everything into this file, and the daemon(s) take it from there. You don't have much other control...
As a final word of warning, the way we have stuff set up here is not the SGI "recommended" way of handling this stuff. They will tell you that we should buy there printer-handling software (impressario?).
Files and Directories...
/var/spool/lp - The directory with all of the lp printer information in it.
/var/spool/lp/log - The log file for lp.
/var/spool/lp/interface/* - The scripts that are run when a print job is submitted.
/var/spool/lp/activeicons/* - Not sure why they must be there, but gives an error if they are missing.
/etc/printcap - The file that defines lpr printers to the print server machine.
/pi/wwrich/bin/printerdef - A script that sets up all of the current printers on a non-print server machine.
/pi/wwrich/bin/printerone - A script that sets up one of the current printers on a non-print server machine.
/pi/wwrich/bin/printer_icons - A script that copies up all of the current printer icons to all machines. (from the one you are currently logged onto).
Troubleshooting...
The first thing to do is to check the log files on both the machine that the print job was submitted on, and the print server it was sent to. Often the log will tell you what the problem is/was. Unfortunately, too many times, the log claims everything is fine.
The most common problems related to printing is the users .rhosts file. This is especially true when that is the ONLY person having problems with printing on that machine. The .rhosts file should contain the line localhost lp. The 2 lines for the machine they are using, plus the two lines for the print server machine must also be present. In addition, the permissions and ownership for this file must be correct. The permission should be 600 (-rw-------), and they must be the owner.
Check the type of file that is not printing. The command file
<name> reports a type. The script that converts files to
PostScript can only deal with certain types. These are: ascii, command,
English, ext, script. Any type that does not contain one of these words will
not be processed. Graphics files are handled separately. TJ wrote the parts of
the script that handle graphics files. Ask him.
If the file is erased before it is finished being printed, this will cause problems. This will appear in the log file as something like "file not found".
Checking the printer daemons is another good thing to try. The command
lpstat -t will give you the full status report on all lp printers.
If a daemon is down or screwed up, you can stop it with lpshut,
and restart it with lpsched. The watcher daemon should inform you
if this daemon is down. The lpstat -t command should also tell
you if the printer in question is not defined (by not telling you about
its status). These checks should be done on both the machine where the request
originated, and the print server machine.
Look at is the script in the /var/spool/lp/interface directory. Is the name of the print server machine correct? Is the name of the printer on the print server correct? In newer versions of IRIX, the machine that creates the print job wants a file in the /var/spool/lp/activeicons directory for each defined printer. If these are missing, copy these file(s) from a machine that has them there. I have a script in ~wwrich/bin that checks for, and copies missing entries into this directory. This script is called printer_icons.
The command lpq -P<printer> will report things in the lpr
queue for a specific printer (if you don't specify a printer, it chooses the
one known as "lp" in the /etc/printcap file). Try the lpc restart
all command to restart the BSD lpr daemons on the print server machine
if things are in the queue and not printing.
Now, check the /etc/printcap file on the print server. Is it there? Can you
ping the names listed as the "rm" entries? Does the nameserver know them?
(nslookup <name>)
Sometimes, I just make the person resend the print job, or I print it myself. Keep in mind the process described in the first part of this document, then try to trace it back. Can you print that file from the print server? Can you print that file from their machine? Can they print that file from the print server? Can they read that file? Can they sign on to the print server?
Setting up a new machine...
Setting up a new printer on a "normal" machine
I have used the printer "k201a" in this example. Of course, you should use
whatever name the new printer should have.
/usr/lib/lpshut - Take the printer daemon down/usr/lib/lpadmin -pk201a -mnetface -v/dev/null - Define the
printers (creates the files in /usr/spool/lp)vi /usr/spool/lp/interface/k201a - Edit the interface file
to add the hostname and printer type info, and the temporary directory to copy
things to.enable k201a - Enable the printer/usr/lib/accept k201a - Tell each printer to accept
jobs/usr/lib/lpsched - Restart the daemonlpstat -p - Check the status/pi/wwrich/bin/printer_icons from the print server
machine (which should already have that printer defined) You only need to do
this once for any single new printer -- it updates all of the machines listed
in the /pi/wwrich/bin/machines file.printerdef and printerone in my bin directory.
Setting up a new printer on the print server machine
cd /var/spool/lp/interfacecp phaserPS <new_printer_name> - This gives you the
correct script.vi <new_printer_name> - Change the name of the
printer from phaserPS to whatever is appropriate. I usually change all
occurances of phaserPS to the new name, and leave everything else alone.cd /var/spool/lp/activeiconscp <pick one> <new name> - Make a copy of one
of the other printer icons for the new one. I think these are which pictures
show up in the GUI printer manager.vi /etc/printcap - Edit this file to add the new printer.
You must know the name that this printer is known as to the nameserver. I
don't really know any good way to figure this out. You can ask the UNIX and/or
printer teams, and sometimes calling the help desk will do it. You will need
to change the "rm" entry to the name that the nameserver knows that printer as.
The "sd" entry should also be changed to use a new directory for the new
printer.mkdir <whatever you told it as the "sd" entry>chmod 775 <whatever you told it as the "sd"
entry>chown daemon.daemon <whatever you told it as the "sd"
entry>lpc restart all - To [re]start the lpr daemons.Last updated: