The print spooler used by the LPRng and lpdfilter printing system is LPRng (lprng).
The print spooler lpd, or line printer daemon, is usually started automatically on boot. More specifically, the script /etc/init.d/lpd is run as part of the boot procedure. After this, the print spooler runs as a in the background. Start and stop it manually with these commands:
rclpd start rclpd stop
These are the configuration files of LPRng:
According to the script /etc/init.d/lpd, the command rclpd start also runs the command checkpc -f as a subprocess, which in turn creates spool directories with the appropriate permissions in /var/spool/lpd according to the queues defined in /etc/printcap.
When started, the print spooler first reads the entries in /etc/printcap to see which print queues have been defined. The spooler's task is then to manage any jobs queued for printing. In particular, the spooler:
manages local queues by passing the print data of each job to a print filter (if necessary) then sending it to the printer or to another queue
handles jobs in the order in which they have been queued
monitors the status of queues and printers and provides status information when requested
listens on port 515 to accept or reject print jobs from remote hosts destined for local queues, depending on the configuration
forwards print jobs to remote print spoolers (listening on port 515 on other hosts) for printing through remote queues.
To learn more about the details of this mechanism, read the LPRng Howto (file:/usr/share/doc/packages/lprng/LPRng-HOWTO.html) or consult printcap and lpd.
Applications use the lpr command for printing. In the application, select the name of an existing queue (such as color) or enter a suitable print command (such as lpr -Pcolor) in the print dialog of the application.
On the command line, you can print with the command lpr -Plp filename. Replace filename with the name of the file you want to print. The option -P can be used to specify the queue. For example, -Pcolor uses the queue color.