How to replace all spaces by underscores in all file names of a folder?

Question

I\'m trying to rename all the files inside a folder (all .exe files). I want to replace all the spaces with underscores, e.g. qwe qwe qwe asd.exe to qwe_q

Answer 1

Based on @Gray answer, I have extending it to replace filenames recursively in all subdirectories.

File 1: replace.bat

setlocal enabledelayedexpansion

set "pattern= "
set "replace=_"

for %%I in (*.ext) do (
    set "file=%%~I"
    ren "%%I" "!file:%pattern%=%replace%!"
)

File 2: recursive.bat

for /d /r . %%D in (*) do (
    copy replace.bat "%%D\replace.bat"
    cd "%%D"
    replace.bat
    del replace.bat
    cd..
)

Files

• replace.bat contains script to replace space with underscore
• recursive.bat contains script to do recursion in all subdirectories

How to use?

• Save both replace.bat and recursive.bat in same directory.
• Replace .ext with desired file extension to match (like .mp4) in replace.bat.
• Double click (run) ONLY recursive.bat file.