

   CCoonnttrrooll MMuullttiippllee DDeevviicceess

        dev.cur()
        dev.list()
        dev.next(which = dev.cur())
        dev.prev(which = dev.cur())
        dev.off(which = dev.cur())
        dev.set(which = dev.next())
        graphics.off()

   AArrgguummeennttss::

      which: An integer specifying a device number

   DDeessccrriippttiioonn::

        These functions provide control over multiple graphics
        devices.

        Only one device is the active device.  This is the
        device in which all graphics operations occur.

        Devices are associated with a name (e.g., "X11"  or
        "postscript") and a number;  the "null device" is
        always device 1.

        `dev.off' shuts down the specified (by default the cur-
        rent) device.  `graphics.off()' shuts down all open
        graphics devices.

        `dev.set' makes the specified device the active device.

        A list of device names is stored in `.Devices'.  The
        name of the active device is stored in `.Device'.

   VVaalluuee::

        `dev.cur' returns the number and name of the active
        device.

        `dev.list' returns the numbers and names of all
        devices.

        `dev.next' returns the number and name of the next
        device in the list of devices.

        `dev.prev' returns the number and name of the previous
        device in the list of devices.

        `dev.off' returns the name and number of the new active
        device (after the specified device has been shut down).

        `dev.set' returns the name and number of the new active
        device.

   SSeeee AAllssoo::

        `Devices', such as `postscript', etc; `graphics.off'
        for closing all devices; `layout' and its links for
        setting up plotting regions on the current device.

   EExxaammpplleess::

        x11()
        plot(1:10)
        x11()
        plot(rnorm(10))
        dev.set(dev.prev())
        abline(0,1)# through the 1:10 points
        dev.set(dev.next())
        abline(h=0, col="gray")# for the residual plot
        dev.set(dev.prev())
        dev.off(); dev.off()#- close the two X devices

