title: How to checkout old git commit including all submodules recursively?
body: <p>I have a git repo with multiple submodules. One of those submodules has multiple submodules of it's own. All I'm looking to do is check out an old commit on the master repo and have it checkout the appropriate commits from all submodules to get the correct state of the code at that time.</p>
  
  <p>I know that git contains the information necessary as the <code>ls-tree</code> command can tell me which commit each submodule was on. However, I have to manually check out each one, which is painfully time consuming.</p>
  
  <p>I'm looking for something like <code>git checkout --recursive</code> but such a command doesn't seem to exist.</p>
  
  <p>Is there anyway to do this?</p>