title: Are concurrent operations possible with Git repositories?
body: <p>There are two scenarios that I'm interested in.</p>
  
  <ul>
  <li>The repository is shared and two users want to push changes to it at the same time</li>
  <li>I want to schedule a nightly or weekly "gc" using a cron job. It runs and someone wants to push or clone during the operation.</li>
  </ul>
  
  <p>Is there a risk of corruption in either of these scenarios?</p>