貌似没有很优美的做法，只能把%Path%按分号分割，然后一段一段地比较。

:InPath [In]Path [Out]0/1

SETLOCAL

SET LocalPathCopy=%PATH%

SET Result=0

:WHILE

IF "%LocalPathCopy" == "" GOTO WEND

FOR /F "delims=;" %%I IN ("%LocalPathCopy%") DO (

IF /I "%%~I" == "%~1" (

SET Result=1

GOTO WEND

)

)

FOR /F "delims=; tokens=1,*" %%I IN ("%LocalPathCopy%") DO (

SET LocalPathCopy=%%~J

)

GOTO WHILE

:WEND

:InPathRet

ENDLOCAL & SET %2=%Result% & GOTO :EOF

使用方法：

SET x=C:Windows

Call :InPath %x% Result

IF %Result% == 0 SET Path=%Path%;%x%