By default, the X authority file referenced by client
    applications and the xauth utility is defined as
    SYS$LOGIN:DECW$XAUTHORITY.DECW$XAUTH. You can override this
    default and specify an alternate X authority file in either of
    the following ways:

    o  You can create alternate X authority files and switch between
       them using the DECW$XAUTHORITY logical. For example, the
       following command changes the X authority file in use for
       the current DECwindows Motif session to UNTRUSTED.DECW$AUTH:

       $  DEFINE DECW$XAUTHORITY-
       _$ SYS$MANAGER:[SYSMGR]UNTRUSTED.DECW$XAUTH

       The logical definition remains in use until it is
       redefined or an alternate value is specified using the SET
       DISPLAY/XAUTHORITY command.

    o  If a display device is used to create a client connection to
       an X server, you can specify an alternate X authority file
       using the SET DISPLAY/CREATE/XAUTHORITY command. Note that the
       file specified on this command line overrides both the default
       and any file referenced by the DECW$XAUTHORITY logical.