for /F "delims=" %%i IN ('dir /b') DO replace C:\dummy.avi "C:\Videos\%%i" /a
for /F "delims=" %%i IN ('dir /b') DO ren "%%i\*.avi" "%%i.avi"
for /F "delims=" %%i IN ('dir /b') DO ren "%%i\%%i.my" info.my
for /F "delims=" %%i IN ('dir /b') DO ren "%%i\%%i.jpg" folder.jpg