6.7. The -Z Passthrough to Filter Options

Options used:

• append_z=Append values to Z options list

• prefix_z=Prefix values to Z options list

• remove_z=Remove values from Z options list

• prefix_s_to_z FLAG Prefix control file S to Z information

• prefix_s_to_z FLAG Prefix control file Z to S information

By convention all of the values specified with the lpr -Z option are placed in the job control file and passed to the lpd server, which turn passes them to the print filters. This allows users to pass options that are not part of the RFC1179 repetoire to filters.

In addition to this simple method of providing options, we can have the lpr and lpd systems add options to the control file information. The prefix_z and append_z options allow us to put Z options at the start or end of the user provided list; the remove_z removes specified options from the list.

The prefix_s_to_z and prefix_z_to_s options are usually used by the lpd server, and provides a simple way to have the SystemV lp -o option values put into the Z options value. This is very useful when existing SysV lp print spooling systems need to be interfaced to LPRng and the options need to be handled in a meaningful manner. The prefix_z_to_s is similarly used when you want to forward jobs to a SysV spooling system and have the options passed correctly.

If present in the printer configuration, the various requested actions are are done by the lpr client, the lpd server on job reception, and the lpd server again on job processing. This redundancy ensures that jobs which are sent to this queue, arrive at this queue, or are processed by this queue have the options set appropriately.