Howto implement manual duplex in CUPS

[Anonymous]

>
> Hello,
>
> On Oct 9 15:30 Anonymous wrote (shortened):
> > 2. Use a special print application like 'duplex'
> > (https://sourceforge.net/projects/duplexpr/) or printDuplex
> > (http://printduplex.sourceforge.net/). These programs first print one
> > side of the pages, prompt the user to switch the paper and then print
> > the opposite sides.
> >
> > The second solution is more flexible, but requires in most programs to
> > save the file and then call the 'duplex' or 'printduplex' program to
> > do the actual printing.
> >
> > Question: what I'm looking for is a way to patch/call these print programs
> > in such way that they can be used in CUPS to define a "pseudoprinter".
> > The pseudoprinter would start with printing odd-pages,
> > prompt for refeeding the paper and then continue with the other sides.
>
> While it is easy to set up an additional queue with an additional
> filtering step which runs such a "manual duplex" program,
> it may become complicated to "prompt for refeeding the paper".
>
> Reason:
> After a print job was submitted to the printing system, the
> processing of the job runs as a different user (e.g. "lp")
> than the user who has submitted the job.
> This different user doesn't have access to the graphical system
> (i.e. the desktop) of the user who has submitted the job.
> Therefore you must find out how "lp" could propmt the user
> who has submitted the job.
>
> Kind Regards
> Johannes Meixner
> --
> SUSE LINUX Products GmbH, Maxfeldstrasse 5      Mail: jsmeix at suse.de
> 90409 Nuernberg, Germany                    WWW: http://www.suse.de/
>


Thanks,

I'm not a Linux Guru, but maybe this can be accomplished by a cron demon, which listens to a message-flag, set by user 'lp'?
The message would contain the name of the user and the message string (eg. "please turn the paper"). The demon polls this flag and sends the message-string to the user.

Btw. this suddenly looks a similar problem as discussed in the thread 'Notification when a print job is not printed'. Only a mail message is not very convenient for the user.
Would such a notifier be helpful?

Peter