windows8批处理更改文件名

@echo off&setlocal EnableDelayedExpansion
set a=1
for /f "delims=" %%i in ('dir /b *.ico') do (
if not "%%~ni"=="%~n0" (
if !a! LSS 10 (ren "%%i" "b0!a!.ico") else ren "%%i" "b!a!.ico"
set/a a+=1
)
)

意思是说把.ico后缀文件更名为bxx.ico,xx为数字