to close the files when you are done with
them.</li>

<li>An empty line is indistinguishable from an EOF with the
command: 

<blockquote><code>set string [gets filename]</code></blockquote>

Use the <code class="keyword">eof</code> command to determine if
the file is at the end or use the other form of <code class=
"keyword">gets</code> (see the example).</li>

<li>You can't overwrite any data in a file that was opened with
<code class="keyword">a</code> (append) <code class=
"arg">access</code>. You can, h