Documentation on device

Key: device
	This keyword is used to specify the plotting device. It uses
	the normal PGPLOT format of

	  file/type

	 or

	  device/type

	Usually there exists a default file name or device name.
	The part after the slash gives the plotter type. Examples of the
	type are:

	  xs	X-windows output. This window is resizeable and
	        persistent. 
	  xd	X-windows output. A transient window that disappears
		when your task exists.
	  ps	Postscript (landscape mode).
	  vps   Postscript (portrait mode).
	  cps   Colour postscript (landscape mode).
	  vcps  Colour postscript (portrait mode).
	  tek	Tektronix 4010 or equivalent.
	  xterm Xterm window (better for simple plots over
		slow X links).

	A `?' as device name generates a complete list of the recognized
	types (which will most likely vary from system to system).

	Files created for hardcopy devices must be spooled to the printer
	separately. The command needed for this is site and device specific.