1

COP 4343Unix System Administration

Unit 9: printing– lpr– CUPS

2

Printing in Unix

• Traditional– Berkeley Line Printer Daemon– AT&T Line Printer System

• Improvements: – typical Linux implementation– LPRng

• Emerging standard– Internet Printing Protocol: IPP/1.1– Common Unix Printing System: CUPS

3

Traditional Linux printing

• PRINTER environment variable

• command line printing: lprex: lpr filename

• print job maintenance– show print queue: lpq– remove job from queue: lprm

4

lpd daemon

• configuration– /etc/printcap

• local or remote printers

– print filters

• queue control per printer– lpc

• status, start, stop

5

Common Unix Printing System

• CUPS manages printers in a network– maintains printer definitions– allows printing to network printers

• maintains lpr commands and /etc/printcap file for backward compatibility

6

CUPS device support

lpinfo -vnetwork socket network http network ipp network lpd network smbserial serial:/dev/ttyS2?baud=115200 direct parallel:/dev/lp1 direct usb:/dev/usb/lp0direct scsi direct hal

7

CUPS setup• cups service

– yum install cups– enable in run-level: chkconfig cups on– start service: service cups start

• configuration – /etc/cups/cupsd.conf

• specify which IP:port to listen onlisten on 127.0.0.1:631

• allow access to Location / and /adminallow from 127.0.0.1

– security: allow tcp port 631 in firewall

8

Common Unix Printing System

• managing CUPS printers– command line interface:

lpadmin

– old style semi-graphical:• printconf

– web interface on port 631http://localhost:631/admin

• printer definitions– ppd files

9

CUPS printer setup

• printer class– for sets of similar printers– jobs accepted to class will print on one

printer in class

• printer setup– local: device– network: protocol + host + name

• ex: “lpd://ferret.cs.fiu.edu/venom”

10

CUPS printer setup

• supported printers– HP, Epson, Okidata, Postscript, ...

• printer options– output resolution, double-sided, banner, ...

11

CUPS printing

• client– PRINTER environment variable– interactive from program

• lpr or lp• lpq• lprm • lpstat