title: Remove files from last git commit
body: <p>This is not the same as <a href="https://stackoverflow.com/questions/12481639/remove-files-from-git-commit">Remove files from Git commit</a>, because all the answers there doesn't work for this case. 
  So here is the question, </p>
  
  <p>Before <code>git commit</code>, we use <code>git add</code>. The problem is when we are doing <code>git add</code>, sometimes we forgot to check and only when doing <code>git commit</code> did we realized that those files should not be picked up by <code>git add</code> are being added and committed. </p>
  
  <p>This is the reason why all the answers there doesn't work, because <code>git reset HEAD^</code> or alike does not work for files newly being picked up, and have not git history beforehand. I learned it the hard way.</p>
  
  <p>So, any solution for this case? Thx. </p>