I have a custom text field that I use for all of my library documents (poor man's tagging). I wish to modify a group in a batch. How do insert a string directly into the text field for all the chosen files?
Hmm not quite sure that I understand exactly but why don't you go into datasheet view for the document library, change the option and simply drag the value down like you would in Excel and this will quickly update the value of the chosen items.
I could be misunderstanding the question though....