title: Can I make git diff ignore permission changes
body: <p>I inadvertedly change the permissions of my entire tree and commit that change along with other content changes.</p>
  <p>I use something like : <pre>tar -czf deploy.tar <code>git diff --name-only v1 v2</code></pre></p>
  <p>to generate  a tar with the modified files between two tags, the problem is that now because of the permissions change almost all my tree is listed as modified.</p>
  <p>Is there a way that I could tell <code>git diff</code> to ignore those files which only has the permissions changed?</p>