title: Rollback yarn command
body: <p>Is there way to rollback command <code>yarn</code> in CLI? </p>
  
  <p>I want check if on server is yarn so i type to CLI <code>yarn</code>... </p>
  
  <p>But immediately i was see:</p>
  
  <pre><code>yarn install v1.22.0
  info No lockfile found.
  [1/4] Resolving packages...
  [2/4] Fetching packages...
  [3/4] Linking dependencies...
  [4/4] Building fresh packages...
  
  success Saved lockfile.
  Done in 0.09s.
  </code></pre>
  
  <p>In directory was other direcoties like: <code>.cache</code> or <code>node_modules</code> and files <code>.yarnrc</code>, <code>yarn.lock</code>....</p>
  
  <p>Is there way to rollback this command?</p>
  
  <p>Is there some options know what EXACTLY was changed and where?</p>
  
  <p>What was on server and what was installed by yarn?</p>