title: regular expression to add characters before and after numbers
body: <p>I have a list of numbers between square brackets, and I need to add words before and after the exact numbers (i.e. keep the same numbers).  I use notepad++ to replace, but if you have a solution with other program please advise.</p>
  
  <p>Example:</p>
  
  <pre><code>text [121] othertext
  moretext [16] othertextmore
  andtext [5940] othertextplus
  </code></pre>
  
  <p>outcome:</p>
  
  <pre><code>text xxxxxxxxx [121] xxxxxxxxx othertext
  moretext xxxxxxxxx [16] xxxxxxxxx othertextmore
  andtext xxxxxxxxx [5940] xxxxxxxxx othertextplus
  </code></pre>
  
  <p>The numbers are of course <code>\d+</code> but I want to tell it to keep the same numbers when looking.</p>