NUMBER_UP=n

    NUMBER_UP specifies the maximum number of pages you can print per
    side of each sheet of paper.  This number of pages will appear on
    each printed side unless you specify a different number through
    a LAYUP_DEFINITION option.  Note that using the LAYUP_DEFINITION
    options can affect the actual number of pages printed per side.
    (A sheet is a physical piece of paper.  A page is an image, which
    would usually be printed on one side of a single sheet.)

    The value n can be from 0 to 100.  If you specify a value of 0,
    layup will be disabled.   If you specify a value of 1, one page
    is printed on a side, reduced, with a border around the page. This
    is useful for including space around the printed page for punching
    holes or for stapling the print job.

    To use NUMBER_UP and a layup definition file together, you must specify
    both on the command line or associate both with a queue.