using <i>upper case</i> characters, e.g. <code>PGPLOT_DIR</code>, not <code>pgplot_dir</code>.</p>

<p>In VMS systems, environment variables are ``logical names'' and can be defined with the <code>DEFINE</code> or <code>ASSIGN</code> command, e.g.</p>

<pre>$ DEFINE PGPLOT_DIR user_disk:[local.pgplot]
$ DEASSIGN PGPLOT_DIR
</pre>

<p>The following environment variables affect all PGPLOT programs:</p>

<dl>
<dt>PGPLOT_DIR</dt>

<dd><i>Directory name.</i> Unless told otherwise by environment variables PGPLOT_