li> `<font color="#82140F"><code>..exit_status..</code></font>'
<!-- latex: \index{@code{..exit_status..}, exit status from @code{system} call} -->
The exit status from the most recent `<font color="#82140F"><code>system</code></font>' call (or 0 if no
system calls have been done yet).
</ul>
<p>




You may use any of these built-in variables anywhere.  For example,
here's how to stack 3 graphs vertically on the page:
<p>
<TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%">
<TR>
<TD>
<PRE>
<f