/p>
<p>The display name or DISPLAY environment variable can be a string in
the format <var>hostname</var>[:<var>number</var>[.<var>screen_number</var>]].
</p>
<p><var>hostname</var> specifies the name of the host machine on which the
display is physically attached. <var>number</var> specifies the number of
the display server on that host machine. <var>screen_number</var> specifies
the screen to be used on that server.
</p>
<p>If unspecified, it defaults to the value of the DISPLAY environment
variable.
</p>