title: How to update user data in cloud formation?
body: <p>I am new to cloud formation ! 
  How do we update the user data in cloud formation, does the update stack also update anything that is changed inside the UserData? If not how do we update the User Data changes ? Thanks !</p>
  
  <pre><code>"UserData": {
      "Fn::Base64": {
          "Fn::Join": [
              "",
              [
                  "#!/bin/bash\n",
                  "apt-get update\n",
                  "apt-get -y upgrade\n",
              ]
          ]
      }
  }
  </code></pre>