The LP print service is a set of software utilities that allows users to print files while they continue to work. Originally, the print service was called the LP spooler.
LP Print Service Directories:
/usr/bin The LP print service user commands
/etc/lp A hierarchy of LP server configuration files
/usr/share/lib The terminfo database directory
/usr/sbin The LP print service administrative commands
/usr/lib/lp The LP daemons; directories for binary files and PostScript filters; and the model directory (which contains the standard printer interface program)
/var/lp/logs The logs for LP activities: lpsched.n – Messages from lpsched and requests.n – Information about completed print requests
/var/spool/lp The spooling directory where files are queued for printing
/var/spool/print The LP print service client-side request staging area
You can check the contents of the configuration files, but you should not edit them directly. Instead, use the lpadmin(1M) command to make configuration changes. Your changes will be written to the configuration files in the /etc/lp directory. The lpsched daemon administers and updates the configuration files.
Print Queue Logs
The scheduler for each system keeps a log of print requests in the directories /var/spool/lp/tmp/system and /var/spool/lp/requests/system. Each print request has two files (one in each directory) that contain information about the request. The information in the /var/spool/lp/requests/system directory can be accessed only by root or lp. The information in the /var/spool/lp/tmp/system can be accessed only by the user who submitted the request, root, or lp.
The LP print service records a history of printing services in two log files: lpsched and requests. These log files are located in the /var/lp/logs directory. You can use the information in these logs to diagnose and troubleshoot printing problems.
# /usr/sbin/lpsched start the LP spooler
# /usr/sbin/lpshut stop the LP spooler