36.12. Managing Print Jobs

When you send a print job to the printer daemon, such as printing text file from Emacs or printing an image from The GIMP, the print job is added to the print spool queue. The print spool queue is a list of print jobs that have been sent to the printer and information about each print request, such as the status of the request, the username of the person who sent the request, the hostname of the system that sent the request, the job number, and more.

If you are running a graphical desktop environment, click the Printer Manager icon on the panel to start the GNOME Print Manager as shown in Figura 36-13.

Figura 36-13. GNOME Print Manager

It can also be started by selecting Main Menu Button (on the Panel) => System Tools => Print Manager.

To change the printer settings, right-click on the icon for the printer and select Properties. The Ferramenta de Configuração da Impressora is then started.

Double-click on a configured printer to view the print spool queue as shown in Figura 36-14.

Figura 36-14. List of Print Jobs

To cancel a specific print job listed in the GNOME Print Manager, select it from the list and select Edit => Cancel Documents from the pulldown menu.

If there are active print jobs in the print spool, a printer notification icon might appears in the Panel Notification Area of the desktop panel as shown in Figura 36-15. Because it probes for active print jobs every five seconds, the icon might not be displayed for short print jobs.

Figura 36-15. Printer Notification Icon

Clicking on the printer notification icon starts the GNOME Print Manager to display a list of current print jobs.

Also located on the Panel is a Print Manager icon. To print a file from Nautilus, browse to the location of the file and drag and drop it on to the Print Manager icon on the Panel. The window shown in Figura 36-16 is displayed. Click OK to start printing the file.

Figura 36-16. Print Verification Window

To view the list of print jobs in the print spool from a shell prompt, type the command lpq. The last few lines will look similar to the following:

Rank   Owner/ID            Class  Job Files       Size Time
active user@localhost+902    A    902 sample.txt  2050 01:20:46

Exemplo 36-1. Example of lpq output

If you want to cancel a print job, find the job number of the request with the command lpq and then use the command lprm job number. For example, lprm 902 would cancel the print job in Exemplo 36-1. You must have proper permissions to cancel a print job. You can not cancel print jobs that were started by other users unless you are logged in as root on the machine to which the printer is attached.

You can also print a file directly from a shell prompt. For example, the command lpr sample.txt will print the text file sample.txt. The print filter determines what type of file it is and converts it into a format the printer can understand.