title: sed trying to replace string with another string
body: <p>i have the following regex command in my bash script: </p>
  
  <pre><code> sed -i -e 's/\(expose_php = On\)/\1expose_php = Off/' /etc/php/php.ini
  </code></pre>
  
  <p>Instead of replacing:</p>
  
  <pre><code>  expose_php = On
  </code></pre>
  
  <p>with </p>
  
  <pre><code>expose_php = Off
  </code></pre>
  
  <p>it's doing the following: </p>
  
  <pre><code> expose_php = Onexpose_php = Off
  </code></pre>
  
  <p>This is my first crack at bash and sed...
  any pointers would be appreciated.</p>