I was faced with this task recently.  Let me paint the picture for you.

I have a document library with over 1,000 items in it.  I added a new column (Named) that needs to have the same information as an existing column (Name).  For whatever reason, the web part I am using for my list search does not recognize the existing column.  I created a SP Designer workflow to copy the contents from the ‘Name’ to the ‘Named’ on creation or edit.

To do this, there are a couple of options.

1. The long drawn out option – Edit each file individually
2. The best option for me – Content and Structure
3. Power option – SharePoint Designer

I went with option 2 because I did not want to lag the server with a whole lot of who ha.  Here are the steps I followed to make this happen.

1. Go to the site, Site Settings, Content and Structure
2. Expand the library to perform this action
   
3. Place a check into the ‘Select All’ check box
   
4. Click on the ‘Actions’ drop down and select ‘Check Out’
   
5. Once checked out (you may have to do this twice), click the ‘Actions’ drop down and select ‘Check In’
   

Make sure to check that you have performed this action for all items in your view.  Mine were in groups of 100, which is generally the standard view.  The fasted option for me would have been the SharePoint Designer route but I did not want to take a chance of checking out over 1,000 items at once and then check them back in.  We already have enough load on the servers from all of the other users accessing SharePoint.