title: open-file-description table is not like what Tanenbaum described in Ubuntu?
body: <p>In the book Modern Operating System, the author explained that if the shell script has two commands, p1 and p2 and each takes turn writing into a file x, the position where p1 finishes will be remembered by p2, as they are using the same open-file-description table. I test this with a simple script.</p>
  <pre class="lang-sh prettyprint-override"><code>#!/bin/bash
  echo 11 &gt; a.txt
  echo 12 &gt; a.txt
  </code></pre>
  <p>It turns out that the second command overwrites the file completely.
  Anything wrong with the script or the implementation?</p>