title: Pulling everything till a specific commit in git
body: <p>I've two servers - Staging and Live.
  I keep my staging server up-to-date so it has all the latest changes push to my git repo.
  Now I want to update my Live server but I don't want to pull everything from my repo but only till a specific commit.</p>
  
  <p>When I do</p>
  
  <pre><code>git status
  </code></pre>
  
  <p>it says </p>
  
  <pre><code># git status
  # On branch master
  # Your branch is ahead of 'origin/master' by 21 commits.
  #
  </code></pre>
  
  <p>When I do </p>
  
  <pre><code>git checkout 7c7f78382fgh9e642d9b3298acacc5903410fefa
  </code></pre>
  
  <p>I get an error...</p>
  
  <pre><code>fatal: reference is not a tree: 7c7f78382fgh9e642d9b3298acacc5903410fefa
  </code></pre>
  
  <p>Any idea what can be wrong.</p>
  
  <p>Do I need to pull everything latest and then do checkout ?</p>
  
  <p>Thanks!</p>