title: Suppress output of variables substitution in sqlplus
body: <p>I'd like to suppress the output of such lines as the following ones</p>
  
  <pre><code>old   9: AND FROMDAT &lt;= TO_DATE('&amp;duedate', 'YYYYMMDD')
  new   9: AND FROMDAT &lt;= TO_DATE('20091031', 'YYYYMMDD')
  old  10: AND TODAT &gt; TO_DATE('&amp;duedate', 'YYYYMMDD')
  new  10: AND TODAT &gt; TO_DATE('20091031', 'YYYYMMDD')
  </code></pre>
  
  <p>How could I achieve this?</p>
  
  <p><code>TERM OFF</code> and <code>FEEDBACK OFF</code> is already set.</p>