Batch-Script: Replace every "@" in file name with "_" in network drive including subfolders

Question

My Problem is this:

I want to replace every Special character such as "@" in file names.

Example:

old file: [email protected]
new file: test_home.txt

This should be done in a special chosen Folder including subfolders. The user should easily Change the Location (Folder).

Well, I will give this a try, but I am not sure how to:

%PATH% = G:\Tests\Folder

::Replace '@' with '_'
   SET [email protected]   
   SET _result=%_test:_=file
   ECHO %_result%          =test_file

Answer 1

setsyntax for replacing a string:

set "var1=my old hat"
set "var2=%var1:old=new%"
echo %var1% was better than %var2%

To get all txt-files:

for %%i in (*.txt) do (
  echo %%i
  rem substitution does not work with special %%i variable type
  set "oldname=%%i"
  set "newname=!oldname:@=_!"
  echo rename "!oldname!" "!newname!"
)

Why ! instead of %? See here