5. LPRng Clients - lpr, lprm, lpq, lpc, lpstat

The LPRng software is a true set of client/server applications. The LPRng clients, lpr, lprm, lpq, and lpc connect to a lpd server using a TCP/IP connection. This means that you must have TCP/IP networking enabled on your workstation to use LPRng.

However, you do not need to have an external network connection to the Internet. For most single system users, the lpd server is running on the same workstation as the client program, and the clients will simply talk to the localhost.

5.1 LPC Commands

The lpc command is the main way that the lpd server is controlled. Here is the help information displayed by the command:

h4: {186} % lpc -=
lpc: Illegal option '='
usage: lpc [-Ddebuglevel][-Pprinter][-Shost][-Uusername][-V] [command]
 with no command, reads from stdin
  -Ddebuglevel - debug level
  -Pprinter    - printer or printer@host
  -Shost       - connect to lpd server on host
  -Uuser       - identify command as coming from user
  -V           - increase information verbosity
 commands:
 active    (printer[@host])        - check for active server
 abort     (printer[@host] | all)  - stop server
 class     printer[@host] (class | off)      - show/set class printing
 disable   (printer[@host] | all)  - disable queueing
 debug     (printer[@host] | all) debugparms - set debug level for printer
 down      (printer[@host] | all)  - disable printing and queueing
 enable    (printer[@host] | all)  - enable queueing
 hold      (printer[@host] | all) (name[@host] | job | all)*   - hold job
 holdall   (printer[@host] | all)  - hold all jobs on
 kill      (printer[@host] | all)  - stop and restart server
 lpd       (printer[@host]) - get LPD PID
 lpq       (printer[@host] | all) (name[@host] | job | all)*   - invoke LPQ
 lprm      (printer[@host] | all) (name[@host]|host|job| all)* - invoke LPRM
 msg printer message text  - set status message
 move printer (user|jobid)* target - move jobs to new queue
 noholdall (printer[@host] | all)  - hold all jobs off
 printcap  (printer[@host] | all)  - report printcap values
 quit                              - exit LPC
 redirect  (printer[@host] | all) (printer@host | off )*       - redirect jobs
 redo      (printer[@host] | all) (name[@host] | job | all)*   - release job
 release   (printer[@host] | all) (name[@host] | job | all)*   - release job
 reread    (printer[@host])        - LPD reread database information
 start     (printer[@host] | all)  - start printing
 status    (printer[@host] | all)  - status of printers
 stop      (printer[@host] | all)  - stop  printing
 topq      (printer[@host] | all) (name[@host] | job | all)*   - reorder job
 up        (printer[@host] | all) - enable printing and queueing
   diagnostic:
      defaultq               - show default queue for LPD server
      defaults               - show default configuration values
      client  (printer | all) - client config and printcap information
      server (printer | all) - server config and printcap

Most of the lpc command line options are common to all LPRng Clients, with the exception of the -S server option. This option allows the lpd host to be explicitly specified.

The lpc commands can be classified as informational, queue management, problem management, job scheduling, and diagnostic.

Informational Commands - status, active, reread

Each spool queue has a Spool Control File, and the lpc status command displays selected values from this file.

The lpc active command connects to the print server and gets the Process ID of the lpd process. This is useful to determine if the lpd server is running on the print server.

The reread command connects to the lpd print server and requests that the server reread the printcap, lpd.conf, and lpd.perms database files.

Queue Management - enable, disable, up, down

The enable and disable commands enable and disable queuing or sending jobs to the print queue. The up command combines the enable and start commands while the down command combines the disable and stop commands.

Printing Management - start, stop, up, down

These commands are used to start and stop printing. The up combines start and enable and down combines stop and disable.

Problem Management - abort, redo, kill

These commands are usually used when there is a problem printing a job. The abort command is used to kill off all printing activity associated with a job. It also has the side effect of stopping printing on the print queue. The redo command will redo or attempt to reprint a job. The kill command combines the abort and redo command, and is useful when there are problems with the job currently being printed and it should be reprinted.

Job Scheduling - topq, holdall, noholdall, hold, release

The topq command effictively puts the select job or jobs at the top of the queue for printing.

The holdall, noholdall, and release commands implement a simple holding queue for jobs. By default, holdall is disabled. When the holdall command enables it, then jobs will remain in the spool queue until explicitly released with the release command.

The hold command can also be used to hold individual jobs until released.

Queue Management - class, redirect, move

The class command is used to restrict printing to jobs whose class value, set using the lpr -C class option, is in the class list or matches one of the classes. This allows the administrator to restrict printing. For more details and an example of its use, see Form Support.

The redirect command allows the administrator to accepts jobs at this queue and then to have them forwarded or redirected to another print queue. This is useful when a printer temporarily is unavailable.

The move command allows an individual job (or jobs) to be forwarded or redirected to another print queue.