The SP.OPEN command sets the "keep open" flag on the default printer, merging multiple print requests into a single print job. The SP.CLOSE command resets this option.
When this mode is set, output directed to the default printer (print unit 0) from successive commands or programs is merged into a single print job. The job is terminated and queued for printing by use of SP.CLOSE or PRINTER CLOSE.
LIST CUSTOMERS,NORTH LPTR
LIST CUSTOMERS,SOUTH LPTR
The above sequence of commands lists records from two elements of the CUSTOMERS multifile as a single print job.