Specifications

168 Chapter 10 Working with the Print Service
CUPS has its own URL, 127.0.0.1:631, which you can access with a web browser. The URL
is independent of the Apache web server, so you do not need to enable web sharing to
use it. You can find the CUPS documentation at www.cups.org.
CUPS includes System V (lp) and Berkeley (lpr) printing commands. CUPS supports
many different file formats, including PostScript and image files, so you can print most
files from the command line.
The CUPS log files, located in /var/log/cups/, include the following:
 access_log, which contains all HTTP requests processed by CUPS server
 error_log, which contains messages from the scheduler (errors, warnings, and so on)
 page_log, which contains a summary of each page sent to a printer
To add a print queue, use the lpadmin tool or the CUPS web interface. When you add a
printer or create a printer pool, you create a CUPS print queue. A PPD file, which
defines the attributes of that queue, is placed in /etc/cups/ppd/. The name of the PPD
file corresponds with the name of the queue (either the name of a printer or the name
of a class). CUPS uses PPD files for non-PostScript printers as well.
The PPD file is copied from another folder on your computer. The standard CUPS
location for PPD files is /usr/share/cups/model/ and its subfolders. The standard
location is in the following folders: /Library/Printers/PPDs/Contents/Resources/ and /
System/Library/Printers/PPDs/Contents/Resources/. The
lpadmin tool can use only PPD
files in /usr/share/cups/model/ and its subfolders.
When you initiate a print job, you generate a CUPS spool file and an IPP attributes file
in /var/spool/cups/. The lp or lpr tool generates an IPP attributes file and spool file.
The spool file is a copy of the original document, so its format is the same as that of the
original file. If the tools do not support a file’s format, you get an error message.
After the file is copied to /var/spool/cups/, cupsd begins preparing the file for printing.
For more information about CUPS and tools specific to CUPS, see the documentation at
www.cups.org/documentation.php.
You can also see the man pages for the following CUPS commands: accept, backend,
cancel, filter, lp, lpadmin, lpinfo, lpoptions, lpq, lpr, lpstat, and reject.
Note: For information about configuring Kerberos support for Print service IPP shared
queues, see Print Service Administration.