Holy cow, I wrote a book!
Somebody wanted to append an extension to all files in a directory
and couldn't find a way to do this type of bulk rename in Explorer.
On the other hand, it's pretty simple from the command prompt:
ren * *.ext
The person then asked,
"Can we get this and other multi-file operations added to Explorer?"
It was not one of Explorer's design goals
to provide a Turing-complete interface for bulk file renaming.
you don't know what you do until you know what you don't do.)
Explorer does an extremely simple type of bulk rename:
Renumbering a group of files.
If that doesn't suit your needs, you can use the command prompt.
Or you can write a batch file that does some editing before
doing the rename.
for %%i in (*.doc) do call :fancy %%i
ren %_% %_:ABC=XYZ%
You can generate a list of files to rename and then load it
into your favorite editor to turn it into a batch file to execute.
dir /b *.vcf > files.cmd
:%s/^\([^ ]*\) \([^ ]*\)\(.*\)/ren "\1 \2\3" "\2 \1\3"
Or you can write a program in your favorite language that does the
most awesome-fancy renaming the world has ever seen.