Process a PostScript file IFILENAME and send it to printer.
Interactively, the command prompts for N-UP printing number, for an input
PostScript file IFILENAME and, when you use a prefix argument (C-u), the
command prompts the user for an output PostScript file name OFILENAME, and
saves the PostScript image in that file instead of sending it to the printer.
Noninteractively, if N-UP is nil, prompts for N-UP printing number. The
argument IFILENAME is treated as follows: if it's t, prompts for an input
PostScript file name; otherwise, it *must* be a string that it's an input
PostScript file name. The argument OFILENAME is treated as follows: if it's
nil, send the image to the printer. If OFILENAME is a string, save the
PostScript image in a file with that name. If OFILENAME is t, prompts for a
file name. (fn N-UP IFILENAME &optional OFILENAME)