bash的字符串相等 [英] bash string equality

问题描述

在庆典，有什么区别，如果有的话，平等的和平等的双重考验运营商之间？

  [A=A]]＆放大器;＆安培;回声等于||回声不等于
[A==A]]＆放大器;＆安培;回声等于||回声不等于
[[一个=b的]＆放大器;＆放大器;回声等于||回声不等于
[A==B]]＆放大器;＆安培;回声等于||回声不等于
 

结果：

 等于
等于
不平等
不平等
 

解决方案

有什么区别， == 是一个同义词 = （用于C / C ++的人，我认为）。请参见这里，例如。

您可以仔细检查刚需的真正的肯定或者只是为了通过查看的兴趣庆典源$ C ​​$ C ，应该是某处解析code，但我不能直截了当找到它。

In bash, what's the difference, if any, between the equal and double equal test operators?

[[ "a" = "a" ]] && echo equal || echo not-equal
[[ "a" == "a" ]] && echo equal || echo not-equal
[[ "a" = "b" ]] && echo equal || echo not-equal
[[ "a" == "b" ]] && echo equal || echo not-equal

results in:

equal
equal
not-equal
not-equal

解决方案

There's no difference, == is a synonym for = (for the C/C++ people, I assume). See here, for example.

You could double-check just to be really sure or just for your interest by looking at the bash source code, should be somewhere in the parsing code there, but I couldn't find it straightaway.

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