The LPRng software has a wide range of facilities to hold or temporarily prevent jobs from printing. Jobs can be individually held or all jobs submitted to a queue can be held until released by an operator. Some administrators use the holdall facility and a cron script to cause jobs to be printed at specific times. The lpc holdall command causes all jobs submitted to a queue to be held until released with the lpc release command. The lpc noholdall command disables the holdall operation.
Edit the printcap file so it has contents indicated below, use checkpc -f to check the printcap, and then use lpc reread to restart the lpd server.
lp:force_localhost
lp:server
:sd=/var/spool/lpd/%P
:lp=lp2@localhost
lp2:force_localhost
lp2:server
:sd=/var/spool/lpd/%P
:lp=/tmp/lp2
Execute the following commands to print the /tmp/hi file and observe the results:
h4: {256} % lpc holdall lp
Printer: lp@h4
lp@h4.private: holdall on
h4: {257} % lpq
Printer: lp@h4 (holdall)
Queue: no printable jobs in queue
h4: {258} % lpr /tmp/hi
h4: {259} % lpq
Printer: lp@h4 (holdall)
Queue: no printable jobs in queue
Holding: 1 held jobs in queue
Server: no server active
Rank Owner/ID Class Job Files Size Time
hold papowell@h4+213 A 213 /tmp/hi 3 09:45:05
h4: {260} % lpc release lp 213
Printer: lp@h4
lp: selected 'papowell@h4+213'
lp@h4.private: started
h4: {261} % lpq
Printer: lp@h4 (holdall)
Queue: no printable jobs in queue
Status: job 'papowell@h4+213' removed at 09:45:22.570
The lpc holdall command causes all jobs to be held. We spool a job, and then use the lpc release command to release the selected job. We disable the holdall operation using the lpc noholdall command.
You can also use the lpc hold command to select individual jobs in a spool queue to be held. This command is useful if there is a set of jobs which require special handling or printing at a later date. The following example shows how this command is used. We use the lpc stop and lpc start commands to simulate the normal delays in print spooling operations.
h4: {263} % lpc stop lp
Printer: lp@h4
lp@h4.private: stopped
h4: {264} % lpq
Printer: lp@h4 (printing disabled)
Queue: no printable jobs in queue
Status: job 'papowell@h4+495' removed at 10:10:50.629
h4: {265} % lpr /tmp/hi
h4: {266} % lpr /tmp/hi
h4: {267} % lpq
Printer: lp@h4 (printing disabled)
Queue: 2 printable jobs
Server: no server active
Rank Owner/ID Class Job Files Size Time
1 papowell@h4+459 A 459 /tmp/hi 3 10:40:32
2 papowell@h4+461 A 461 /tmp/hi 3 10:40:34
h4: {268} % lpc hold lp 459
Printer: lp@h4
lp: selected 'papowell@h4+459'
lp@h4.private: updated
h4: {269} % lpq
Printer: lp@h4 (printing disabled)
Queue: 1 printable job
Holding: 1 held jobs in queue
Server: no server active
Rank Owner/ID Class Job Files Size Time
1 papowell@h4+461 A 461 /tmp/hi 3 10:40:34
hold papowell@h4+459 A 459 /tmp/hi 3 10:40:32
In the next example we show how to use the lpc hold command to select and hold an individual job. Then we start the queue and see what happens:
h4: {270} % lpc start
Printer: lp@h4
lp@h4.private: started
h4: {271} % lpq
Printer: lp@h4
Queue: no printable jobs in queue
Holding: 1 held jobs in queue
Server: no server active
Status: job 'papowell@h4+461' removed at 10:41:24.873
Rank Owner/ID Class Job Files Size Time
hold papowell@h4+459 A 459 /tmp/hi 3 10:40:32
h4: {272} % lpc release lp 459
Printer: lp@h4
lp: selected 'papowell@h4+459'
lp@h4.private: started
h4: {273} % lpq
Printer: lp@h4
Queue: no printable jobs in queue
Status: job 'papowell@h4+459' removed at 10:41:39.457
As we see, the held job is not printed until we release it, and then is processed normally.
The printcap :ah (autohold) option has the same effect as the lpc holdall command but its actions cannot be disabled by the lpc noholdall command.