title: How does git handle the placement of a git repository inside another?
body: <p>I have been reading an article in which the author instructed: creating a new repository within an existing one, and wondered if it was an error he overlooked. I will verify with him later.</p>
  
  <p>These are the conditions I want to check:</p>
  
  <ol>
  <li><p>The condition when an existing directory is made into a repository,
  and files already checked into the main project are also checked in
  the new (sub) repository. Is this possible?</p></li>
  <li><p>When a directory tree which contains git repositories is checked in
  for the first time</p></li>
  <li><p>When a new empty repository is created under the repository, either
  by git init, or by copying a .git repository into a new or empty
  directory?</p></li>
  </ol>