Views Bulk Operation module is helpful in the cases where we need to perform a particular operation for more than one row in a view. Some of the operations includes deleting multiple contents, publishing/un-publishing contents, change the author of the content, send email etc. In one of our Drupal project I need to perform a action to add a single field for all rows. Drupal provides a hook to declare the required operations and handle extra changes to the bulk operations settings.