title: How do you clone ( duplicate ) a MongoDB object in a collection of the same db?
body: <p>I need to duplicate (clone) an object in the collection via dbshell. Having something like this :</p>
  
  <pre><code>&gt; db.users.distinct( 'nickname' )
  [
          "user1",
          "user2",
          "user3",
          "user4"
  ]
  &gt;
  </code></pre>
  
  <p>where user1 select a complex object in <strong>users</strong> collection, how can I duplicate the object then change (rename) user1 field in userX ?</p>