CUPS
CUPS is the standards-based, open source printing system developed by OpenPrinting for Linux® and other Unix®-like operating systems.
Arch Linux packages the OpenPrinting CUPS fork, not the Apple CUPS fork.
Installation
Optionally, install the cups-pdf package if you intend to "print" into a PDF document. By default, PDF files are stored in /var/spool/cups-pdf/username/
. The location can be changed in /etc/cups/cups-pdf.conf
.
Then enable and start cups.service
or alternatively use socket activation to only start CUPS when a program wants to use the service.
Print steps
It is important to know how CUPS works if wanting to solve related issues:
- An application sends a PDF file to CUPS when 'print' has been selected (in case the application sends another format, it is converted to PDF first).
- CUPS then looks at the printer's PPD file (printer description file) and figures out what filters it needs to use to convert the PDF file to a language that the printer understands (like PJL, PCL, bitmap or native PDF).
- The filter converts the PDF file to a format understood by the printer.
- Then it is sent to the back-end. For example, if the printer is connected to a USB port, it uses the USB back-end.
Connection interfaces
Additional steps for printer detection are listed below for various connection interfaces.
USB
To see if your USB printer is detected, make sure you have the usbutils package installed, then:
$ lsusb
(...) Bus 001 Device 007: ID 03f0:1004 Hewlett-Packard DeskJet 970c/970cse
Parallel port
To use a parallel port printer, the lp
, parport
and parport_pc
kernel modules are required.
# dmesg | grep -i parport
parport0: Printer, Hewlett-Packard HP LaserJet 2100 Series lp0: using parport0 (polling)
Network
Adding known location printers
It is not required to rely on dynamic printer discovery on the network (DNS-SD/mDNS) when the address of the printer is known (e.g. obtained via printers display or other network scanning approaches). A CUPS queue can be directly added to use the printer. Documentation for adding the queue with lpadmin can be found in following sections and official documentation at Setting up printers.
Printer discovery
To discover, make use of discovered or share printers using DNS-SD/mDNS, setup .local hostname resolution with Avahi and restart cups.service
.
avahi-daemon.service
running for SD (Service Discovery) itself.To share printers with Samba, e.g. if the system is to be a print server for Windows clients, the samba package will be required.
Printer drivers
Most recent printers (2010+) support driverless usage by implementing AirPrint and/or IPP_Everywhere (c.f. below).
The drivers for a printer may come from any of the sources shown below. See CUPS/Printer-specific problems for an incomplete list of drivers that others have managed to get working.
To drive a printer, CUPS needs a PPD file and, for most printers, some filters. For details on how CUPS uses PPDs and filters, see [1].
The OpenPrinting Printer List provides driver recommendations for many printers. It also supplies PPD files for each printer, but most are available through foomatic or the recommended driver package.
When a PPD file is provided to CUPS, the CUPS server will regenerate the PPD files and save them in /etc/cups/ppd/
.
To test if they are working before creating a PKGBUILD, PPD files can be manually added to /usr/share/cups/model
, the driver should be available after the next restart of the cups service.
AirPrint and IPP Everywhere
CUPS includes support for AirPrint and IPP Everywhere printers. These should be discovered automatically.
OpenPrinting CUPS filters
The Linux Foundation's OpenPrinting workgroup provides cups-filters. Those are backends, filters, and other binaries that were once part of CUPS but have been dropped from the project. They are available in the cups-filters package that is a dependency of cups.
Non-PDF printers require ghostscript to be installed. For PostScript printers, gsfonts may also be required.
Foomatic
The Linux Foundation's OpenPrinting workgroup's foomatic provides PPDs for many printer drivers, both free and non-free. For more information about what foomatic does, see Foomatic from the Developer's View.
To use foomatic, install foomatic-db-engine and at least one of:
- foomatic-db — a collection of XML files used by foomatic-db-engine to generate PPD files.
- foomatic-db-ppds — prebuilt PPD files.
- foomatic-db-nonfree — a collection of XML files from printer manufacturers under non-free licenses used by foomatic-db-engine to generate PPD files.
- foomatic-db-nonfree-ppds — prebuilt PPD files under non-free licenses.
The foomatic PPDs may require additional filters, such as min12xxwAUR.
Gutenprint
The Gutenprint project provides drivers for Canon, Epson, Lexmark, Sony, Olympus, Brother, HP, Ricoh, PCL printers and some generic printers for use with CUPS and GIMP.
Install gutenprint and foomatic-db-gutenprint-ppds.
cups-genppdupdate
as root and restart CUPS. cups-genppdupdate will update the PPD files of the configured printers, see cups-genppdupdate(8) for more details.Manufacturer-specific drivers
Many printer manufacturers supply their own Linux drivers. These are often available in the official Arch repositories or in the AUR.
Some of those drivers are described in more detail in CUPS/Printer-specific problems.
Printer URI
Listed below are additional steps to manually generate the URI if required. Some printers or drivers may need a special URI as described in CUPS/Printer-specific problems.
USB
CUPS should be able to automatically generate a URI for USB printers, for example usb://HP/DESKJET%20940C?serial=CN16E6C364BH
.
If it does not, see CUPS/Troubleshooting#USB printers for troubleshooting steps.
Parallel port
The URI should be of the form parallel:device
. For instance, if the printer is connected on /dev/lp0
, use parallel:/dev/lp0
. If you are using a USB to parallel port adapter, use parallel:/dev/usb/lp0
as the printer URI.
Network
If you have set up Avahi as in #Network, CUPS should detect the printer URI. You can also use avahi-discover
to find the name of your printer and its address (for instance, BRN30055C6B4C7A.local/10.10.0.155:631
).
The URI can also be generated manually, without using Avahi. A list of the available URI schemes for networked printers is available in the CUPS documentation. As exact details of the URIs differ between printers, check either the manual of the printer or CUPS/Printer-specific problems.
The URI for printers on SMB shares is described in the smbspool(8) man page.
lpadmin: Bad device-uri
error.
For example, smb://BEN-DESKTOP/HP Color LaserJet CP1510 series PCL6
becomes smb://BEN-DESKTOP/HP%20Color%20LaserJet%20CP1510%20series%20PCL6
.
This result string can be obtained by running the following command:
$ python -c 'from urllib.parse import quote; print("smb://" + quote("BEN-DESKTOP/HP Color LaserJet CP1510 series PCL6"))'
Remote CUPS print servers can be accessed through a URI of the form ipp://hostname:631/printers/queue_name
. See CUPS/Printer sharing#Printer sharing for details on setting up the remote print server.
See CUPS/Troubleshooting#Networking issues for additional issues and solutions.
Usage
CUPS can be fully controlled using the lp* and cups* CLI tools. Alternatively, the #Web interface or one of several #GUI applications can be used.
- The queue name is a short but descriptive name used on the system to identify the queue. This name should not contain spaces or any special characters. For instance, a print queue corresponding to a HP LaserJet 5P could be named "hpljet5p". More than one queue can be associated with each physical printer.
- The location is a description of the printer's physical location (for instance "bedroom", or "kitchen"). This is to aid in maintaining several printers.
- The description is a full description of the print queue. A common use is a full printer name (like "HP LaserJet 5P").
CLI tools
See CUPS local documentation for more tips on the command-line tools.
Use SNMP to find a URI:
$ /usr/lib/cups/backend/snmp ip_address
lp*
The lpinfo command lists the URI of the printers connected to your system with the -v
flag, and lists all of the available drivers (or "models", in CUPS parlance) installed on your system with -m
.
The lpadmin utility creates a new queue with -p queue_name
. The -E
flag added to -p
enables and accepts jobs on the printer. The -v
flag specifies the device URI. The -m
flag specifies the driver (or "model", in CUPS parlance) or PPD file to use.
You can also use the -x
flag to remove a printer (read #cups* beforehand).
Examples :
# lpadmin -p HP_DESKJET_940C -E -v "usb://HP/DESKJET%20940C?serial=CN16E6C364BH" -m drv:///HP/hp-deskjet_940c.ppd.gz
For a driver-less queue (Apple AirPrint or IPP Everywhere):
# lpadmin -p AirPrint -E -v "ipp://10.0.1.25/ipp/print" -m everywhere
For a raw queue; no PPD or filter:
# lpadmin -p SHARED_PRINTER -m raw
When specifying a PPD instead of a model:
# lpadmin -p Test_Printer -E -v "ipp://10.0.1.3/ipp/print" -m pxlmono.ppd
- When specifying the PPD, use just the file name and not the full path (for instance,
pxlmono.ppd
instead of/usr/share/ppd/cupsfilters/pxlmono.ppd
). Alternatively, the full path can be used with the-P
command line switch. - As of 2021, many recent printers support driverless printing setup and when specifying
-m everywhere
, as in the second example above, the printer will be defined and a .ppd file will be created in/etc/cups/ppd/
by querying the printer on the network.
The lpq utility checks the queue. Add the -a
flag to check on all queue.
The lprm utility clears the queue. Add a -
to remove all entries instead of only the last one by default.
The lpr utility prints. Use -# N
to print the file N times, use the -p
flag to add a header.
Examples of test prints using lpr:
$ lpr /usr/share/cups/data/testprint $ echo 'Hello, world!' | lpr -p
The lpstat utility, used with the -s
flag, checks the status. The -p
flag allows to specify which queue to check.
The lpoptions utility uses the same -p queue_name
flag as lpadmin shown above. With the -l
flag, it lists the options. The -d
flag sets the default printer with the argument queue_name
. The -o
flag sets options to a value:
$ lpoptions -p HP_DESKJET_940C -o PageSize=A4 $ lpoptions -p HP_DESKJET_940C -o cupsIPPSupplies=true -o Duplex=DuplexNoTumble
cups*
The cupsaccept, cupsdisable, cupsenable and cupsreject utilities do as they are called. Respectively: setting the printer to accept jobs, disabling a printer, activating a printer, setting the printer to reject all incoming tasks.
As an example of their usage, we will cleanly remove a printer:
# cupsreject queue_name # cupsdisable queue_name # lpadmin -x queue_name
ink
Install inkAUR to view the ink levels.
Add your user to the additional lp
user group, log out and log in again.
For usage information, run ink
without options.
Web interface
The CUPS server can be fully administered through the web interface, available on http://localhost:631/.
To perform administrative tasks from the web interface, authentication is required; see #Permissions.
- Add a queue
Go to the Administration page.
- Modify existing queues
Go to the Printers page, and select a queue to modify.
- Test a queue
Go to the Printers page, and select a queue.
GUI applications
If your user does not have sufficient privileges to administer CUPS, the applications will request the root password when they start. To give users administrative privileges without needing root access, see #Configuration.
- Deepin Print Manager — Printer configuration interface for Deepin desktop.
- GtkLP — GTK interface for CUPS.
- print-manager — Tool for managing print jobs and printers (KDE).
- system-config-printer — GTK printer configuration tool and status applet.
Configuration
The CUPS server configuration is located in /etc/cups/cupsd.conf
and /etc/cups/cups-files.conf
(see cupsd.conf(5) and cups-files.conf(5)). After editing either file, restart cups.service
to apply any changes. The default configuration is sufficient for most users.
Permissions
Groups
User groups with printer administration privileges are defined in SystemGroup
in the /etc/cups/cups-files.conf
. The sys
and root
and wheel
groups are used by default.
CUPS helper programs are run as the cups
user and group. This allows the helper programs to access printer devices and read configuration files in /etc/cups/
, which are owned by the cups
group.
lp
group was used instead. After the upgrade, the files in /etc/cups
should be owned by the cups
group and User 209
and Group 209
set in /etc/cups/cups-files.conf
.Allowing admin authentication through PolicyKit
PolicyKit can be configured to allow users to configure printers using a GUI without the admin password.
Here is an example that allows members of the wheel user group to administer printers without a password:
/etc/polkit-1/rules.d/49-allow-passwordless-printer-admin.rules
polkit.addRule(function(action, subject) { if (action.id == "org.opensuse.cupspkhelper.mechanism.all-edit" && subject.isInGroup("wheel")){ return polkit.Result.YES; } });
Default paper size
cups is built with libpaper support and libpaper defaults to the Letter paper size (called PageSize
in lpoptions
). To avoid having to change the paper size for each print queue you add, edit /etc/papersize
and set your system default paper size. See paper(1).
Archival PDF/A
To save PDF files in the highly compatible format, normally called Archival PDF, or PDF/A, or PDFA, or ISO 19005.
There is currently no option, so it must be added to the command used by cups to call gs.
/etc/cups/cups.conf
# GSCall %s -q -dCompatibilityLevel=%s -dNOPAUSE -dBATCH -dSAFER -sDEVICE=pdfwrite -sOutputFile="%s" -dAutoRotatePages=/PageByPage -dAutoFilterColorImages=false -dColorImageFilter=/FlateEncode -dPDFSETTINGS=/prepress -c .setpdfwrite -f %s # the above line shows the default for the GSCall value. Add -dPDFA before -dNOPAUSE and remove the comment prefix: (do not copy the line from here as it might have changed. use the "default" from your own file) GSCall %s -q -dCompatibilityLevel=%s -dPDFA -dNOPAUSE -dBATCH -dSAFER -sDEVICE=pdfwrite -sOutputFile="%s" -dAutoRotatePages=/PageByPage -dAutoFilterColorImages=false -dColorImageFilter=/FlateEncode -dPDFSETTINGS=/prepress -c .setpdfwrite -f %s
Log files
By default, all logs are sent to files in /var/log/cups/
.
The log level can be changed in /etc/cups/cupsd.conf
. See cupsd.conf documentation.
By changing the values of the AccessLog
, ErrorLog
, and PageLog
directives in /etc/cups/cups-files.conf
to syslog
, CUPS can be made to log to the systemd journal instead. See Fedora:Changes/CupsJournalLogging for information on the original proposed change.
cups-browsed
CUPS can use Avahi browsing to discover unknown shared printers in your network. This can be useful in large setups where the server is unknown. To use this feature, set up .local hostname resolution, and start both avahi-daemon.service
and cups-browsed.service
. Jobs are sent directly to the printer without any processing so the created queues may not work, however driverless printers such as those supporting IPP Everywhere or AirPrint should work out of the box.
- Searching for network printers may significantly increase the time it takes for your computer to boot.
cups-browsed.service
is only needed to dynamically add and remove printers as they appear and disappear from a network. It is not required if you simply want to add a DNS-SD/mDNS supporting network printer to CUPS.
Print servers and remote administration
See CUPS/Printer sharing and CUPS/Printer sharing#Remote administration.
Without a local CUPS server
CUPS can be configured to directly connect to remote printer servers instead of running a local print server. This requires installation of the libcups package. Some applications will still require the cups package for printing.
To use a remote CUPS server, set the CUPS_SERVER
environment variable to printerserver.mydomain:port
. For instance, if you want to use a different print server for a single Firefox instance (substitute printserver.mydomain:port
with your print server name/port):
$ CUPS_SERVER=printserver.mydomain:port firefox
To make this configuration permanent create configuration file /etc/cups/client.conf
and add a hostname of the remote CUPS server to it:
ServerName server
You can also specify a custom port:
ServerName server:port
See [4] for details.
Troubleshooting
See CUPS/Troubleshooting and CUPS/Printer-specific problems.
See also
- Official CUPS documentation, locally installed
- Wikipedia:CUPS
- OpenPrinting homepage
- OpenSuSE Concepts printing guide - explains the full printing workflow
- OpenSuSE CUPS in a Nutshell - a quick CUPS overview
- Gentoo:Printing
- Debian's Printing portal - detailed technical guides
- Debian's printing overview - a basic view of the CUPS printing system
- CUPS printing-architecture and printing-users mailing lists
- CUPS mailing list (Apple fork)
- CUPS issues tracker
- CUPS issues tracker (Apple fork)