title: Git: add file to old commit being parent of a new branch already merged back?
body: <p>given the following git log, how do i add a file (which never existed in any commit) to commit B, so that this new file will appear in every other commit that A?</p>
  <pre><code>A --&gt; B -----&gt; D ------&gt; F
         \--&gt; C --&gt; E --/
  </code></pre>
  <p>In my attempts with git rebase --onto i did not succeed in not having to essentially duplicate every commit amending the contents but i am sure i am not approaching it using the full power of git. Any help?</p>
  <p>Note: remote is fine to be forced, or even deleted and pushed again, that's not a worry.</p>
  <p>Thanks a lot</p>