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NAME | DESCRIPTION | ENVIRONMENT | FILES | CONFORMING TO | NOTES | SEE ALSO | COPYRIGHT | COLOPHON |
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cups(1) OpenPrinting cups(1)
cups - a standards-based, open source printing system
CUPS is the software you use to print from applications like word
processors, email readers, photo editors, and web browsers. It
converts the page descriptions produced by your application (put a
paragraph here, draw a line there, and so forth) into something
your printer can understand and then sends the information to the
printer for printing.
Now, since every printer manufacturer does things differently,
printing can be very complicated. CUPS does its best to hide this
from you and your application so that you can concentrate on
printing and less on how to print. Generally, the only time you
need to know anything about your printer is when you use it for
the first time, and even then CUPS can often figure things out on
its own.
HOW DOES IT WORK?
The first time you print to a printer, CUPS creates a queue to
keep track of the current status of the printer (everything OK,
out of paper, etc.) and any pages you have printed. Most of the
time the queue points to a printer connected directly to your
computer via a USB port, however it can also point to a printer on
your network, a printer on the Internet, or multiple printers
depending on the configuration. Regardless of where the queue
points, it will look like any other printer to you and your
applications.
Every time you print something, CUPS creates a job which contains
the queue you are sending the print to, the name of the document
you are printing, and the page descriptions. Job are numbered
(queue-1, queue-2, and so forth) so you can monitor the job as it
is printed or cancel it if you see a mistake. When CUPS gets a job
for printing, it determines the best programs (filters, printer
drivers, port monitors, and backends) to convert the pages into a
printable format and then runs them to actually print the job.
When the print job is completely printed, CUPS removes the job
from the queue and moves on to any other jobs you have submitted.
You can also be notified when the job is finished, or if there are
any errors during printing, in several different ways.
WHERE DO I BEGIN?
The easiest way to start is by using the web interface to
configure your printer. Go to "http://localhost:631" and choose
the Administration tab at the top of the page. Click/press on the
Add Printer button and follow the prompts.
When you are asked for a username and password, enter your login
username and password or the "root" username and password.
After the printer is added you will be asked to set the default
printer options (paper size, output mode, etc.) for the printer.
Make any changes as needed and then click/press on the Set Default
Options button to save them. Some printers also support auto-
configuration - click/press on the Query Printer for Default
Options button to update the options automatically.
Once you have added the printer, you can print to it from any
application. You can also choose Print Test Page from the
maintenance menu to print a simple test page and verify that
everything is working properly.
You can also use the lpadmin(8) and lpinfo(8) commands to add
printers to CUPS. Additionally, your operating system may include
graphical user interfaces or automatically create printer queues
when you connect a printer to your computer.
HOW DO I GET HELP?
The OpenPrinting CUPS website
(https://openprinting.github.io/cups) provides access to the cups
and cups-devel mailing lists, additional documentation and
resources, and a bug report database. Most vendors also provide
online discussion forums to ask printing questions for your
operating system of choice.
CUPS commands use the following environment variables to override
the default locations of files and so forth. For security reasons,
these environment variables are ignored for setuid programs:
CUPS_ANYROOT
Whether to allow any X.509 certificate root (Y or N).
CUPS_CACHEDIR
The directory where semi-persistent cache files can be found.
CUPS_DATADIR
The directory where data files can be found.
CUPS_ENCRYPTION
The default level of encryption (Always, IfRequested, Never,
Required).
CUPS_EXPIREDCERTS
Whether to allow expired X.509 certificates (Y or N).
CUPS_GSSSERVICENAME
The Kerberos service name used for authentication.
CUPS_SERVER
The hostname/IP address and port number of the CUPS scheduler
(hostname:port or ipaddress:port).
CUPS_SERVERBIN
The directory where server helper programs, filters, backend,
etc. can be found.
CUPS_SERVERROOT
The root directory of the server.
CUPS_STATEDIR
The directory where state files can be found.
CUPS_USER
Specifies the name of the user for print requests.
HOME Specifies the home directory of the current user.
IPP_PORT
Specifies the default port number for IPP requests.
LOCALEDIR
Specifies the location of localization files.
LPDEST
Specifies the default print queue (System V standard).
PRINTER
Specifies the default print queue (Berkeley standard).
TMPDIR
Specifies the location of temporary files.
~/.cups/client.conf
~/.cups/lpoptions
CUPS conforms to the Internet Printing Protocol version 2.1 and
implements the Berkeley and System V UNIX print commands.
CUPS printer drivers, backends, and PPD files are deprecated and
will no longer be supported in a future feature release of CUPS.
Printers that do not support IPP can be supported using
applications such as ippeveprinter(1).
cancel(1), client.conf(5), cupsctl(8), cupsd(8), lp(1),
lpadmin(8), lpinfo(8), lpoptions(1), lpr(1), lprm(1), lpq(1),
lpstat(1), CUPS Online Help (http://localhost:631/help),
OpenPrinting CUPS Web Site (https://openprinting.github.io/cups),
PWG Internet Printing Protocol Workgroup (http://www.pwg.org/ipp)
Copyright © 2020-2024 by OpenPrinting.
This page is part of the CUPS (a standards-based, open source
printing system) project. Information about the project can be
found at ⟨https://github.com/openprinting/cups⟩. If you have a
bug report for this manual page, see
⟨https://github.com/OpenPrinting/cups/issues⟩. This page was
obtained from the project's upstream Git repository
⟨https://github.com/openprinting/cups⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-08-07.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
2021-02-28 CUPS cups(1)
Pages that refer to this page: cups-oauth(1), cups-x509(1), ippeveprinter(1), client.conf(5), cups-files.conf(5), backend(7), filter(7), cupsd(8), cupsd-helper(8), cupsfilter(8), cups-lpd(8)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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