UnForm is designed to work as a filter, accepting standard text input from your application’s print runs, analyzing the text, and adding enhancements and process control while sending the job out to the printer. Typically, this output is routed through spooling software such as EasySpooler.

A typical interface to a printer via EasySpooler would use the “llp” spooling command, like this:

|uf90c -f <rulefile> | llp -odatat=c -d<printername>

If the destination is a lpr printer, then a filter code can be used to turn off filtering at the server end:

|uf90c -f <rulefile> | llp -Fl -d<printername>

The purpose of the -odatat=c and -Fl (that’s -F and the letter “ell”) options is to force pass-through processing of UnForm’s output. The -odatat=c option specifies PCL output. An alternative is to specify binary output with odatat=b, although EasySpooler is then unable to count pages and therefore can’t provide page control features, such as restarting a job at a particular page.