Windows CMD - set within for loop is not working

Question

I want to write batch file which will loop through all directories containing backup directory and remove files older than X days within it. On computer which I want run my

Answer 1

You need to use delayed expansion to read a variable that you have set inside a for loop.

Try this instead

setlocal enabledelayedexpansion
rem we will memorize current directory
pushd %cd%
set folder="C:\Documents and Settings\myname\Desktop"
cd %folder%
rem loop only folders with five chars within their names (unfortunately on less also
for /D %%g in (?????) DO (
    set checkpath="%cd%\%%g\backup"
    if exist !checkpath! (
        for %%a in ('%%g\backup\*.*') do (
        set FileDate=%%~ta
        set FileDate=!%FileDate:~0,10%!
        rem here I want to compare file modification data with current date
        )
    )
popd
pause

Replacing the %'s with !'s on variables you have created will signal it to use delayed expansion instead.