As described in the Print Spooling Overview, the information in the printcap database is used control printing operations. While there is no RFC specifying its format or content, there is a strong de facto standard for its format. For a complete description of the printcap database see Printcap Database. For a list of all of the printcap and configuration options see Index To All The Configuration and Printcap Options.
Here is a sample printcap suitable for use by the LPRng clients:
LPRng use :lp for destination (device and spool queue) lp:lp=lp@h4.private lpreal:lp=/dev/lp0 Vintage BSD uses :rp:rm for spooler queue and :lp for device lp:rp=lp:rm=h4.private lpdev:lp=/dev/lp0
The :lp=lp@h4.private printcap entry tells the client programs that jobs for the lp printer or print queue are sent to the lp print queue queue on host h4.private. This can also be specified using the The legacy BSD :rp and :rm. The :rp=queue option specifies the print queue :rm=host option specifies the host. When both lp and :rp:rm are present the :lp option has precedence.
On the printserver the following is a sample printcap entry suitable for the lpd server:
The :sd=directory option (spool queue directory) specifies the directory where print jobs will be placed. The %P will be replaced with the name of the spool queue. The :lp literal is now the path to the output device the lpd server will use to print the job. The :filter literal specifies the filter program to use to process the job before sending to the output device.
Here is another example of a printcap entry using the %P notation:
This entry will cause all jobs sent to the lp spool queue to be sent to the lp queue on server. %X strings in the printcap entries are expanded as shown: