title: sed command in dry run
body: <p>How it is possible to make a dry run with <code>sed</code>?</p>
  
  <p>I have this command:</p>
  
  <pre><code>find ./ -type f | xargs sed -i 's/string1/string2/g'
  </code></pre>
  
  <p>But before I really substitute in all the files, i want to check what it WOULD substitute. Copying the whole directory structure to check is no option!</p>