In order to view the DVI file, the machine on which you are working must be able to send x-windows output to your display. Therefore, the machine must know where your display is. If it does not know, it gives you a message similar to the title of this section. You must set the DISPLAY variable.
If your display is directly attached to a unix machine (e.g. fuji), then type (substitute machine name for fuji)
at the prompt. If you are at an x-terminal, then you must find an IP address for that terminal. In most cases, it will be taped to the display, or you might also find it in one of the dialog boxes that comes up when you log on. If your IP address is 188.8.131.52 then type
at the command prompt. Note the extra :0 at the end.