为什么找不到FindStr返回 [英] Why is FindStr returning not-found

问题描述

%vData%等于包含;%main%\Programs\Go\Bin的HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment\Path变量.
%main%是同一环境中的变量，其保留值C:\Main.

%vData% equals the HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment\Path variable which includes ;%main%\Programs\Go\Bin.
%main% is a variable in the same Environment which holds the value C:\Main.

我想在添加之前检查此值是否存在，所以我有代码:

I want to check if this value exists before adding, so I have the code:

echo %vData% | FindStr /L /I /C:"%%main%%\\Programs\\Go\\Bin"

我尝试了%%main%%和%main%和%^main%和%^^main%，但是它始终告诉我该字符串不存在.

I have tried %%main%% and %main% and %^main% and %^^main% but it consistently tells me the string does not exist.

如何获取它以证明它确实存在?

How do I get it to show me it does exist?

推荐答案

鉴于该变量确实包含文字字符串;%main%\Programs\Go\Bin(您可以通过简单地执行echo/%vData%来证明它)，我相信您正在寻找它:

Given that the variable really contains the literal string ;%main%\Programs\Go\Bin (you can prove it by simply doing echo/%vData%), I believe that you are looking for this:

echo/%%vData%%| findstr /I /C:"%%main%%\\Programs\\Go\\Bin"

，甚至更好，因为vData中的特殊字符受到保护:

or, even better, since special characters in vData become protected:

cmd /V /C echo(!vData!| findstr /I /C:"%%main%%\\Programs\\Go\\Bin"

---

您的代码有问题:

---

The problem with your code:

echo %vData% | FindStr /L /I /C:"%%main%%\\Programs\\Go\\Bin"

是在新的cmd实例中执行管道|的任一侧的事实 在新的|的左侧>实例，因为它是内部命令[由于在这个问题] ，因此变量vData扩展了两次:

is the fact that either side of the pipe | is executed in a new cmd instance the left side of the pipe | is executed in a new cmd instance since it is an internal command [updated due to the finding handled in this question], so variable vData is expanded twice:

1. 当执行整个命令行时，左侧变为:

1. when the whole command line is executed, the left side becomes:

echo ...;%main%\Programs\Go\Bin

在执行管道的左侧时，它变为:

when the left side of the pipe is executed, it becomes:

echo ...;C:\Main\Programs\Go\Bin

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