How to resume CUPS printer from command line

Question

Hello I have printer in CUPS that due driver problems (hp 1010) form time to time goes into pause. I would like to write a shell script that will be once per hour resuming printer in cups. But I have no idea after googling for couple of minutes how to resume printer from shell command line.

Regards Stan

Answer 1

The -E option of lpadmin should do that. You can probably just create a cron job with the lpadmin command.

lpadmin [ -E ] [-U username ] [ -h server[:port] ] -p printer option(s)

Hourly cron entry:

0 * * * * /usr/sbin/lpadmin -E -p your_printer

You can add that by running:

sudo crontab -e

Answer 2

There's the cupsenable command.

cupsenable printer

starts a disabled printer.

You may have to run the command as root or through sudo. So if you have to enable the printer in a shell script, you would have to add the shell to root's crontab, or edit your sudoers file.

Answer 3

As others have already said, 'cupsenable' or 'lpadmin -E' should do the trick.

A related issue is IIRC that by default CUPS configures the printer such that if printing a job fails somehow, the printer is disabled. You can change this to abort the job instead.

Answer 4

Your problem could be tackled in different ways, depending on the version of CUPS you're running.

More recent versions of CUPS come with a builtin functionality that could help here. It's called "ErrorPolicy". It's default setting is selected in cupsd.conf, and determines how cupsd should handle print queues which do not behave as expected. You have 3 choices to tag to each queue individually:

ErrorPolicy abort-job  
ErrorPolicy retry-job  
ErrorPolicy retry-this-job  
ErrorPolicy stop-printer  

abort-job

-- Abort this job and proceed with next job in same queue

retry-job

-- Retry this job after waiting for N seconds (where N is determined by cupsd.conf's "JobRetryInterval" directive).

retry-this-job

-- Retry current job immediately and indefinitely.

stop-printer

-- Stop current print queue and keep the job for future printing. This is still the default, unless you define otherwise as per above mentioned alternatives It also was default + only possible behaviour for all queues in previous versions of CUPS (the one you do want to get rid of as per your question).

Additionally, you can set individual ErrorPolicies to each separate print queue. This setting would be noted in the printers.conf file. (Set it from a commandline with lpadmin -p printername -o printer-error-policy=retry-this-job).

For older versions of CUPS I'd recommend to have a look at beh, the CUPS BackEnd Handler. beh is a wrapper which can be applied to any CUPS backend.

Assuming your print queue currently has defined a backend of socket://192.168.1.111:9100, and it behaves in the way you don't like (being disabled by cupsd from time to time due to network connection problems). With beh you'd re-define your backend like this:

beh:/0/20/120/socket://192.168.1.111:9100

This would retry a job 20 times in two minute intervals, and disable the queue only when still not succeeding. Or you could do this:

beh:/1/3/5/socket://192.168.1.111:9100

This retries the job 3 times with 5 second delays between the attempts. If the job still fails, it is discarded, but the queue is not disabled. You want to let cupsd try indefinitely to connect to the device? Good, try this:

beh:/1/0/30/socket://192.168.1.111:9100

Try infinitely until printer comes back. Intervals between connection attempts are 30 seconds. The job does not get lost when the printer is turned off. You can intentionally delay printing simply by switching off the printer. A good configuration for desktop printers and/or home users.

Overall, there is no need to mess around with bash scripts, cron jobs, lpadmin, cupsenable or sudo in order to re-activate CUPS queues going down erratically.