如何保持它采用＆QUOT一个Windows批处理脚本外的变量的值;延迟扩展本地＆QUOT;模式？ [英] How to keep the value of a variable outside a Windows batch script which uses "delayed expansion local" mode?

问题描述

上下文：我需要通过添加另一个路径来调用Windows批处理脚本，将更新我的 PATH XXX 在它的结束，但是：

Context: I need to call a Windows batch script which would update my PATH by adding another path 'xxx' at the end of it, but:

• 没有任何重复的结果
  （如果我添加 XXX '像一个路径 AAA; XXX; BBB '，我需要一个更新的 PATH 像 AAA，BBB，XXX '）


• 无任何聚集结果
  （我可以反复调用脚本，而不带结束了 AAA，BBB，XXX，XXX，XXX; ... '）

• without any duplicate
  (if I add 'xxx' to a PATH like 'aaa;xxx;bbb', I need an updated PATH like 'aaa;bbb;xxx')
• without any aggregation
  (I can call the script repeatedly without ending up with 'aaa;bbb;xxx;xxx;xxx;...')

我曾尝试：

下面的函数接受任何重复的关心和做这项工作。

The following function takes care of any duplicate and does the job

: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

但是，它需要 延迟扩展本地模式，这意味着：在年底脚本（或在这里，在函数 cleanAddPath 的结束），无论已设置为％PATH％是扔掉

But, it needs delayed expansion local mode, which means: at the end of the script (or here, at the end of the function cleanAddPath), whatever has been set for %PATH% is thrown away.

我可以问的用户（这是我写的剧本）推出他们的 CMD 与 CMD / V：ON 选项（激活延迟扩展，否则默认关闭），但是这是不实际的。

I could ask the users (for which I write the script) to launch their cmd with a cmd /V:ON option (activating the delayed expansion, otherwise off by default), but that is not practical.

我如何修改 PATH 可变我上面描述的，仍然有它在我目前的DOS会话更新方式的之后的呼吁表示脚本？

How can I modify the PATH variable the way I described above, and still have it updated in my current DOS session after calling said script?

推荐答案

页面 DOS - 功能集提供了有关如何函数可以在DOS下返回一个值，即使在使用很好的例子延迟扩展方式：

The page "DOS - Function Collection" gives great example on how a function can return a value in DOS, even when using delayed expansion mode:

下面的函数将更新与另外你想要的任何变量 PATH ：

The following function will update any variable you want with an addition PATH:

: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

请注意使用路径串联。由于杰布 <一个href=\"http://stackoverflow.com/questions/12020152/how-to-keep-the-value-of-a-variable-outside-a-windows-batch-script-which-uses/12020153#comment16267108_12020153\">comments:

Note the concatenation of paths using. As jeb comments:

行集P =％P％;％〜2 是至关重要的，如果你的路径包含像＆符号在 C：\\文件和放大器;设置。结果
  最好换将 P =;！％〜2

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".

的 SET％〜1 =％P％是允许记忆（按 psented变量重新$ P $部分％〜1 ）已使用延迟扩展等功能设置的值。结果
我最初使用 SET％〜1 =％P％！，但杰布 <一个href=\"http://stackoverflow.com/questions/12020152/how-to-keep-the-value-of-a-variable-outside-a-windows-batch-script-which-uses/12020153#comment16267108_12020153\">comments:

The SET "%~1=%P%" is the part which allows to memorize (in the variable represented by %~1) the value you have set using delayed expansion features.
I initially used SET "%~1=%P%" !, but jeb comments:

命令 SET％〜1 =％P％！可以简化为 SET％〜1 =％P％作为结尾感叹号具有延迟扩展模式，如果你prepared ％p％之前只有一个（好）的效果。

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.

要更新您的 PATH 变量，你会叫你的函数：

To update your PATH variable, you would call your function with:

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

和将离开该脚本，为当前DOS会话后仍然存在。

And it will persists after leaving that script, for your current DOS session.

dbenham 的回答指向一个更强大的答案（upvoted），但对我来说这个脚本已经足够了。

dbenham's answer points to a more robust answer (upvoted), but in my case this script is enough.

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