title: Show all commits whose diff contain specific string
body: <p>As the title says, I want to find every commit whose diff contains specific string.</p>
  
  <p>At the moment, I use   </p>
  
  <pre><code>git log -p 'filename'
  </code></pre>
  
  <p>Which shows less like interface of every diff, where I search for the string.
  Then I backtrace to find the actual commit msg.</p>
  
  <p>Simple alternative might be to pipe git log -p into grep, but I can not find the commit id or message that way.</p>