007你给我进来，Come in,please!
http://blog.csdn.net/ljc007/archive/2010/04/17/5496729.aspx

::Question:
::ＬＪＣ /*
::这样怎么扩充变量　%%B

setlocal enabledelayedexpansion
FOR /F "usebackq tokens=* delims=" %%i in (`dir /ad /b`) do (
set b=%%~ti%
echo !a!
echo !b!
if !a! leq %%b:~0,-6%% echo %%b:~0,-6%%
set a=%%b:~0,-6%%
)
pause

:: */

[解决办法]