How to use the SFU_Print Queues on CECM CentOS 7 Computers
Table of Contents
- 1) Command-line printing basics
- 2) Printing from a GUI application
- 3) Print job authentication using the GNOME desktop
- 3a) Print job authentication when printing from the command-line in GNOME
- 3b) Print job authentication when printing from a GUI application in GNOME
- 4) The PaperCut Client App
- 5) Printing without the GNOME desktop
- 6) Print job pre-authentication with Kerberos
1) Command-line printing basics
To see what printers are available, type
laserwriter accepting requests since Wed 06 Mar 2019 11:33:12 PM PST laserwriter-single accepting requests since Wed 06 Mar 2019 11:33:12 PM PST lw accepting requests since Wed 06 Mar 2019 11:33:12 PM PST lw-single accepting requests since Wed 06 Mar 2019 11:33:12 PM PST SFU_Print accepting requests since Thu 07 Mar 2019 03:23:23 PM PST SFU_Print-colour accepting requests since Thu 25 Oct 2018 12:55:41 AM PDT SFU_Print-colour-single accepting requests since Tue 19 Mar 2019 02:54:14 PM PDT SFU_Print-single accepting requests since Thu 25 Oct 2018 12:55:39 AM PDT
To see if there are any stuck print jobs, type
SFU_Print-colour-single-7 username 302080 Tue 19 Mar 2019 03:22:06 PM PDT SFU_Print-8 username 145408 Tue 19 Mar 2019 03:22:51 PM PDT
If a stuck print job belongs to you and you want to get rid of
it, you can use the
cancel command, as
NOTE: Every time you print, you should check
the print queues with
Alternatively, if the print job is stuck because it is awaiting authentication, you can authenticate it.
To print a pdf file, say "topopromo.pdf" to the SFU_Print-colour
queue, just type
2) Printing from a GUI application
Although you can print a pdf file from the command-line, you might first want to view it using a graphical application and print it from there. For such purposes, I recommend that you use evince or atril. evince is the GNOME document viewer and atril is the MATE document viewer. Or if you prefer the KDE desktop environment, then you can use okular. They are all open-source and supported by most Linux distributions.
Do not use acroread! If you try to print from acroread to one of the SFU_Print queues, the job will fail and it will remain stuck in the local queue on your computer. If you view the print queue, you'll see that the problem isn't that the job status is "Held for authentication" but, rather, it will be Stopped. This is due to "filter errors". The bottom line is that acroread is not compatible with the SFU_Print drivers.
The problem is that Adobe stopped supporting acroread on Linux many years ago. One hasn't been able to download it for a long time. The installer that I use to put acroread on Fedora Linux and CentOS Linux is a very old one that I snagged way back before Adobe dropped support. It's surprising that it even runs at all.
Whatever GUI application you use for printing, it will have a print menu that most likely comes with tabbed sub-menus for adjusting such things as duplex, colour, and resolution. For example, here's what the evince print menu looks like:
You might be confused, because SFU_Print-colour isn't necessarily colour and SFU_Print-single isn't necessarily single-sided! Those queues names validly represent the printer output only when printing from the command-line, and the settings will be overridden by what you choose in the GUI print menu. Furthermore, whatever you choose for one of the SFU_Print queues will be set for all of them. For example, if you choose single-sided colour printing for one of the SFU_Print queues, say "SFU_Print-colour-single", they will all be set to single-sided colour printing!
In order to avoid confusion, you should "SFU_Print" for all GUI printing, whether it is black and white or colour; single-sided or duplex, and set the options accordingly each time you print.
3) Print job authentication using the GNOME desktop
3a) Print job authentication when printing from the command-line in GNOME
If you are running a GNOME desktop session on a CECM CentOS 7 computer, then, when you print a file on the command-line (in a Terminal window) to one of the SFU_Print queues, you should see a notification similar to the following pop up on your screen:
If you're not using Kerberos pre-authentication, then this will be followed shortly thereafter by the following notification:
If you click on the latter notification window before it disappears, it will take you to a print job authentication window like the following:
You can then hit the Authenticate button, and type in your Campus username and password. NOTE: this is not necessarily the same as your CECM password! The CECM uses its own authentication system which is independent from the Campus auth system.
After successful authentication, the PaperCut App will respond.
If the "Authentication Required" notification disappears before you have a chance to click on it, or if you never saw it in the first place, you can still bring up the Job Authentication window as follows. First, click in the upper right-hand corner of the header of your GNOME desktop in order to bring up the settings menu, which will look something like this:
And then click on the button which has a crossed wrench and screwdriver logo on it (circled in red above), in order to bring up the GNOME Control Center. Scroll through the settings to "Devices" and then click on "Printers". It should look something like this:
Scroll down to the SFU_Print Queues section. If there is a job sitting in one of the queues, you'll see it listed as shown circled in red below:
Just click on that button (circled in red above) and you'll get the Job Authentication window as shown previously.
3b) Print job authentication when printing from a GUI application in GNOME
If you're printing from a GUI application in GNOME, you'll get a different job authentication window than that shown above. If you're not using Kerberos pre-authentication, then you should see a Job Authentication window similar to the following pop up on your screen:
As above, type in your Campus username and password. NOTE: this is not necessarily the same as your CECM password! The CECM uses its own authentication system which is independent from the Campus auth system.
If you click on the "Remember password" box, your Campus password will be saved into your keychain, and you won't have to type it every time you print from a GUI application.
After successful authentication, the PaperCut Client App will respond.
If, for some reason, the Print Job Authentication window doesn't show up its own, you can still bring it up manually, as shown above.
4) The PaperCut Client App
The accounting system used by the SFU_Print queues is called "PaperCut". It keeps track of how many pages you print. The PaperCut Client App talks to the PaperCut server, and it is set to start automatically when you log into a GNOME session on a CECM CentOS 7 computer. It looks like this:
When you successfully authenticate to an SFU_Print queue, the PaperCut Client App will put up a window similar to the following:
If you see this window, that means your print job was successful, and that all you have to do is go to the printer and tap your key fob to the sensor in order to release your printing. If you don't have a key fob, you can type in your Campus username and password on the printer's LCD screen.
If you don't see this window, then that most likely means that something went wrong and your job will not reach the printer.
5) Printing without the GNOME desktop
If you are logged into a CECM CentOS 7 server via ssh, then the GNOME desktop won't be available to you. You can still print via the command-line, but authenticating an SFU_Print job presents an extra challenge.
The best way to authenticate your print job is to use Kerberos pre-authentication. Unfortunately, this option is currently broken in CentOS 7 due to a bug in samba.
The second best way to authenticate your print job this is to make sure that you're running X-Windows on your client computer. If you're logged into a GUI desktop (such as MATE or GNOME) of a Linux workstation, then it's already running X-Windows. (The GUI is an environment built on top of X-Windows.)
If you're using a Mac, then make sure you have XQuartz installed.
If you're using Windows, then you need to install MobaXterm.
Then, in a Terminal window of your Linux workstation or Mac, or
in a MobaXterm window of your Windows computer, type
If you want to verify that X-Windows is working, just type
In order to authenticate your print job, type
Go to the "Printer" menu of this window
Just right-click on your stuck print job and choose "Authenticate" from the pop-up menu:
You'll need to use your Campus username and password. If you're on a CECM workstation that is running the PaperCut Client App, it will pop up its notification window and you'll know that your print job was successful and is awaiting release at the printer.
Even if you're on a home computer or a laptop that isn't running the PaperCut Client App, it is still possible that your print job was successful. You won't know for sure until you go to the printer to release your job. (But if you leave it for too long, it'll disappear.)
6) Print job pre-authentication with Kerberos
Kerberos printing on CentOS 7 is currently broken due to a bug in the newer versions of samba. When this bug has been fixed, this documentation will be updated.
For more details on this, please see our Kerberos Printing FAQ.
Research Computing Group
IT Services, SFU Last modified: Wed Apr 10 17:18:15 PDT 2019