Exist a Drush command to update all the contents?
You can take a look inside the module Drush Entity because in this module you have the command entity-update:

drush @drupal.d7 entity-update node 53 --fields=title


If you want to improve the command to work in all nodes you can read this post:

How to adapt the name of a custom Drush command?

EDIT: 

If you want to learn about Drush alias (@drupal.d7) you can go to: Drush Aliases: What, Why and How