In order to run a WWW browser on an X windows display, the environment variable DISPLAY should first be defined to identify the display you want to use. HTX only supports WWW browsers which use X displays.
If you are a regular user of an X display, you will probably already have the necessary command in your .login file. If not, you may want to use the Starlink xdisplay command (described in SUN/129) to make the appropriate definition.
If HTX detects that the DISPLAY variable has not been defined, it
will attempt to run the xdisplay utility itself before starting a
WWW browser. For this to succeed, xdisplay must be installed on
your system and the directory /star/bin must be on your UNIX PATH. If the
xdisplay command cannot be found (and the DISPLAY
environment variable is undefined), then an error will result.
Because the xdisplay command may take some time to complete, you will be warned if this must be repeated by each subsequent HTX command (not all WWW browsers require this), as it will slow down your access to documents. Defining the DISPLAY environment variable yourself will eliminate this delay.