Figure 2-16. Printer configuration window
2.5.1.1. Add a new print queue
USB and parallel printers, as well as network printers that use the Internet Print Protocol (IPP), will be detected and configured automatically; you can adjust the printer configuration by editing the values in the main printer-configuration window (Figure 2-16) and then clicking Apply.
Other printers must be configured manually. Click on the New Printer icon to access the window shown in Figure 2-17.
Figure 2-17. New Printer window
Enter the name of the printer, which should be short and contain no spaces. I recommend using the generic printer type followed by a number (e.g., laser3 or inkjet0 ); even if you only have one printer now, you may add more in the future. If desired, you can add verbose description and location information. Click Forward to proceed to the connection configuration step, shown in Figure 2-18 .
Figure 2-18. Printer connection configuration
The Devices list shows all detected local printers, plus serial ports and common network printing protocols. Select the appropriate option; for network printers, you will need to enter the IP address or hostname as well as the printer or queue name. Press Forward to proceed to the driver configuration step, shown in the left side of Figure 2-19. Select the printer manufacturer, then click Forward; on the next display (shown on the right side of Figure 2-19), select the printer model. Use the Comments buttons to display information about the printer, driver, or PPD file.
The Drivers list may present more than one driver option. In almost all cases, it is best to use the default driver.
Click Forward, then click Apply on the confirmation dialog that appears.
Figure 2-19. Printer driver selection
2.5.1.2. Edit an existing print queue
To change an existing queue configuration, select the printer in the main window (Figure 2-16) and edit the option values on the tabs:
Settings
Configures the printer description, location, connection details, printer driver, and printer status (enabled/accepting/shared). Enabled means the the queue contents will be sent to the printer; accepting means that new print requests may be enqueued.
Policies
Configures starting and ending banner pages (which identify each print job) and the action to be taken when a printer error occurs.
Access control
Used to restrict printer access to specific users, or to prevent specific users from accessing the printer.
Printer options
Configures the default settings for printer features such as stapling, duplexing, media, ink cartridge type, and resolution.
2.5.1.3. Set the default print queue
The default print queue is used for all print requests that do not specify a queue. To set the default, select a printer and then click Make Default Printer. Click Apply to activate your change.
2.5.1.4. Printing
The command lpr (line printer requester) is used to place a print request into a queue. When used from the command line, lpr can accept input from standard input or from a specified file. For example, to print the file output.ps :
$ lpr output.ps
Or to print the calendar for the year, generated by the cal -y command:
$ cal -y | lpr
To specify a specific print queue (such as laser3 ), add the -P argument along with the name of the queue:
$ lpr -P laser3 output.ps
$ cal -y | lpr -P laser3
You can view the status of a print queue, including the documents in the queue, by clicking on the printer icon that appears in the notification area of the GNOME panel bar. The window shown in Figure 2-20 will appear; this window shows all print requests made by you on all print queues. To delete a document from the queue, right-click on it and select the Cancel document option.
Figure 2-20. Document print-status window
The lpq command provides another way of viewing a queue's contents:
$ lpq
inkjet0 is ready
no entries
While the graphical Document print-status window shows requests by one user on all queues, lpq shows requests by all users on a single queue. The output in the previous example shows that there are no documents in the default queue inkjet0 . You can specify a specific printer queue using the -P argument:
$ lpq -P laser3
laser3 is ready and printing
Rank Owner Job File(s) Total Size
active chris 91 report.ps 124928 bytes
2 jason 92 spreadsheet.ps 523423 bytes
In this case, there are two jobs in the queue; job 91 is printing, and job 92 is scheduled to be printed next.
You can delete a document using the lprm command, which accepts a job number (the default is the active job) and the -P option to specify the print queue. This command will delete job 92 on the print queue laser3 :
$ lprm -P laser3 92
2.5.2. How Does It Work?
Fedora's printing system combines four fairly complex tools into a comprehensive print solution. The Common Unix Printing System (CUPS) provides queue management and printer sharing; the Foomatic system provides access to the large database of printer configuration information and notes maintained by linuxprinting.org; Ghostscript converts PostScript, the most common printer output format used by Linux applications, into other formats for use by non-PostScript printers; and the system-config-printer script provides the user interface for printer configuration.
system-config-printer manipulates the CUPS configuration files in /etc/cups and restarts the CUPS server (cupsd) to load configuration changes. These files can be edited by hand, but this is not recommended.
CUPS provides queue management, storing queued documents in /var/spool/cups until they are printed. It is heavily tied into the Internet Print Protocol (IPP), which is based on the web protocol HTTP. You can connect to the CUPS server's administrative interface by accessing the address http://localhost:631 / through a web browser; however, if you do any configuration through that interface, you may no longer be able to use system-config-printer , which is generally a better configuration tool.