It was probably a lisp program that used ObjectDBX much like Lee Mac's custom program called "Batch Find & Replace Text".  Here is a description of the program......

This program uses ObjectDBX to perform multiple text replacements on the current drawing, all open drawings, or a complete directory (and optionally subdirectories) of drawings. The program has the ability to search Text, MText, Block Attributes, Multileader Text, Table Cell Text, Dimension Override Text and all of these items within Block Definitions.



Edited by John Connor - 12.Jun.2014 at 16:09

And are you working in a sheet set or are they disparate drawings?

You had one command to do this previously?  Perhaps it was a custom lisp routine.

One option would be to batch process the folder containing the 1000+ drawings using a script.  Once started the script will open a drawing, make the change, possibly do a purge and audit along with a zoom > extents then save the drawing.  The script keeps repeating the procedure for all the drawings in the folder until it is done.  The drawback is if the script encounters something it was unprepared for then it will stop.  You could find yourself coming in the next day expecting all the drawings to have been revised and saved only to find that only a few drawings had been revised before the script stop working.