title: How to increment a number in several files if the number is not always the same?
body: <p>I have several files containing this line</p>
  
  <pre><code>Release: X
  </code></pre>
  
  <p>I want to increment X in all the files. </p>
  
  <p>If X was constant between the files, I could have a bash script looping around the files and doing ($1 containing the former release number and $2 the new one, ie. $1 + 1) :</p>
  
  <pre><code>sed 's/Release: '$1'/Release: '$2'/' &lt;$file &gt;$file.new
  </code></pre>
  
  <p>Now, how should I do if the release number is different between files ? </p>
  
  <p>Is it doable with sed ? </p>
  
  <p>should I use another tool ?</p>