在批处理文件中使用调用时，是否可以逃脱％? [英] Is there a way to escape % while using call in batch file?

问题描述

这是我的第一个批处理脚本.我试图转义％char，以便不将其用作变量.使用start时，双精度%%可以工作，但是当我使用%%进行调用时，请输入空格和缺少函数的参数.

This is my first batch script. I was trying to escape % char so that is not used as variable. Double %% works when using start, but when I use %% with call it input en empty space and function missing parameter.

在使用通话时是否可以逃脱％?

call wp rewrite structure %%postname%% << FAILED
start wp rewrite structure %%postname%% << OK

我只是想知道为什么带有开始"的相同语句能按预期工作，而呼叫"却缺少参数.两者都使用附加的％char来转义百分号.

I was just wondering why is that same statement with "start" worked as expected and "call" was missing an argument. Both were escaping percent sign using additional % char.

推荐答案

我认为您的确定"行是正确的，因为您希望使用文字％postname％，并且您知道百分比文字必须为通过在批处理文件中加倍来逃脱.

I presume your "OK" line is OK because you want the literal %postname%, and you recognize that percent literals must be escaped by doubling within a batch file.

如果未将百分比加倍，则将％postname％扩展为环境变量postname的值(如果未定义，则为空字符串).

If you don't double the percents, then %postname% is expanded to the value of environment variable postname (or empty string if not defined).

CALL导致对百分比进行两次评估.第一轮百分比扩展将 %% postname %% 转换为％postname％.那就是你想要的.但是，随后由CALL启动的第二轮操作将％postname％扩展为变量值.

CALL causes percents to be evaluated twice. The first round of percent expansion converts %%postname%% into %postname%. That is what you want. But then the second round initiated by CALL causes %postname% to be expanded to the variable value.

解决方案很简单，第二次将百分比翻倍:

The solution is simple, double the percents a second time:

call wp rewrite structure %%%%postname%%%%

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