Variable: pr-file-duplex
pr-file-duplex is a customizable variable defined in printing.el.gz.
Value
nil
Documentation
Non-nil means print PostScript file in duplex mode.
Source Code
;; Defined in /usr/src/emacs/lisp/printing.el.gz
(defcustom pr-file-duplex nil
"Non-nil means print PostScript file in duplex mode."
:type 'boolean)