Код:

@echo off
setlocal enableextensions enabledelayedexpansion
set sSourceFolder=C:\ftp\rpo
2>nul pushd "%sSourceFolder%" && (
for /f "usebackq delims=" %%i in (
`2^>nul dir /b /a:-d`
) do (
set sVar=%%~i
ren "%%~i" "!sVar:*-=!"
)
popd
) || (
echo Can't find source folder [%sSourceFolder%]
exit /b 1
)
endlocal
exit /b 0