Sometimes you need to update a lot of items. Sometimes datasheet mode doesn't cut it.
* indicates a required field.
Enter the display name or the GUID of the source list (e.g. “Announcements” or “{A123AB12-AB1A-12A1-1234-ABC1A1234A12}”).
Enter the path to the site or sub-site where the source list is located (e.g. “http://Server/Site”).
Enter the CAML Query to select the items you want to update. By default this selects all items.
Click the Preview button to view all of the items that will be updated. This will not perform the actual updates.
Add any fields that you want to update, then select how you want to update them.
Warning: Make sure your lists and updates are set properly and you've run a preview to ensure that the correct list items will be updated. Once this process begins it can only be stopped by closing your browser tab/window. It cannot be undone.