title: Bash scripting: How do I parse the output of a command and perform an action based on that output?
body: <p>I am using wget to grab some files from one of our servers once an hour if they have been updated. I would like the script to e-mail an employee when wget downloads the updated file.</p>
  
  <p>When wget does not retrieve the file, the last bit of text wget outputs is</p>
  
  <pre><code>file.exe' -- not retrieving.
  &lt;blank line&gt;
  </code></pre>
  
  <p>How do I watch for that bit of text and only run my mail command if it does not see that text?</p>