title: unix tr find and replace
body: <p>This is the command I'm using on a standard web page I <code>wget</code> from a web site.</p>
  
  <pre><code>tr '&lt;' '\n&lt;' &lt; index.html
  </code></pre>
  
  <p>however it giving me newlines, but not adding the left broket in again.
  e.g.</p>
  
  <pre><code> echo "&lt;hello&gt;&lt;world&gt;" | tr '&lt;' '\n&lt;'
  </code></pre>
  
  <p>returns </p>
  
  <pre><code> (blank line which is fine)
   hello&gt;
   world&gt;
  </code></pre>
  
  <p>instead of </p>
  
  <pre><code> (blank line or not)
   &lt;hello&gt;
   &lt;world&gt;
  </code></pre>
  
  <p>What's wrong?</p>