How can I update all content of a content type with a newly added field? I have a content type with a set of fields.

Hundred(s) of pieces of content have been created from this content type.

I recently had to go back and add a new field to the content type.

In order for all content of that content type that I previously created to show the newly added field, I have so far been going into each piece of content and adding in the field. This is going to take forever.

Is there another tool or process I can use to update all previously created content with the new field added to the content type?
if I understand correctly you need to update node in range of new date? right? so if this is the case why not use EntityFieldQuery() to list of this nodes then node_save() or field_attach_update() to update the new value.

if this is the case I'd be happy to give you some snippets to help you do this.