The following process works with all WordPress versions after version 3.7. There are several other options for enabling automatic background updates for WordPress including but not limited to: utilizing Jetpack with WordPress.com and utilizing WordPress plugins.
For a refresher on editing files with vim see: New User Tutorial: Overview of the Vim Text Editor
Navigate to your root WordPress directory (in this case: /home/example/public_html) and edit the wp-config.php file:
Add the following to the file:
/* Enable Automatic Background Updates for WordPress Core */
define( ‘WP_AUTO_UPDATE_CORE’, true );
In this case, I added the above code just above:
/* That’s all, stop editing! Happy blogging. */
Then exit and save the file with the command :wq .