title: sed + remove string only in the last line of the file
body: <p>I use the following sed command to remove the <code>line number</code> string from file</p>
  
  <pre><code>sed -i s'/line number//g' file
  </code></pre>
  
  <p>but what I need to change in  <code>sed</code> syntax in order to remove the <code>line number</code>
  only if it exist in the last line of the file?</p>