如何将变量的值保留在使用“延迟扩展本地”模式的Windows批处理脚本之外？

:cleanAddpath -- remove %~1 from PATH,add it at the end of PATH
SETLOCAL ENABLEDELAYEDEXPANSION
set PATH=!PATH:%~2=!
set PATH=!PATH:;;=;!
set PATH=%PATH%;%~2
set P=!P:;;=;!
echo %PATH%
echo -------------
ENDLOCAL  
exit /b

页面“ DOS – Function Collection”提供了一个很好的例子,说明函数如何在DOS中返回值,即使使用 delayed expansion模式：

以下函数将使用添加PATH更新所需的任何变量：

:cleanAddpath -- remove %~2 from %~1,add it at the end of %~1
SETLOCAL ENABLEDELAYEDEXPANSION
set P=!%~1!
set P=!P:%~2=!
set P=!P:;;=;!
set P=!P!;%~2
set P=!P:;;=;!
(ENDLOCAL & REM.-- RETURN VALUES
  SET "%~1=%P%"
)
exit /b

请注意使用的路径串联.截止日期：jeb comments：

The line set P=%P%;%~2 is critical if your path contains ampersands like in C:\Documents&Settings.
Better change to set “P=!P!;%~2“.

SET“％~1 =％P％”是允许记忆(在由％~1表示的变量中)使用延迟扩展特征设置的值的部分.
我最初使用SET“％~1 =％P％”!,但是jeb comments：

The command SET "%~1=%P%" ! Could be simplified to SET "%~1=%P%" as the trailing exclamation mark has only a (good) effect in delayed expansion mode and if you prepared %P% before.

要更新PATH变量,可以使用以下命令调用函数：

call :cleanAddpath PATH "C:\my\path\to\add"

对于当前的DOS会话,它将在离开该脚本后继续存在.

dbenham的answer指向一个更健壮的答案(upVoted),但在我的情况下这个脚本就足够了.