"-ne"是什么意思?卑鄙的意思? [英] What does "-ne" mean in bash?

问题描述

bash脚本中的命令"-ne"是什么意思?

What does the command "-ne" mean in a bash script?

例如，bash脚本的以下行是做什么的?

For instance, what does the following line from a bash script do?

[ $RESULT -ne 0 ] 

推荐答案

如果您不知道在哪里看，这是很难搜索的东西之一.

This is one of those things that can be difficult to search for if you don't already know where to look.

[实际上是一个命令，不是您可能期望的bash shell语法的一部分.它恰好是Bash内置命令，因此已在Bash手册中进行了记录.

[ is actually a command, not part of the bash shell syntax as you might expect. It happens to be a Bash built-in command, so it's documented in the Bash manual.

还有一个外部命令可以执行相同的操作；在许多系统上，它是由GNU Coreutils软件包提供的.

There's also an external command that does the same thing; on many systems, it's provided by the GNU Coreutils package.

[与test命令等效，除了[要求]作为其最后一个参数，而test不需要.

[ is equivalent to the test command, except that [ requires ] as its last argument, and test does not.

假设系统上已安装bash文档，如果键入info bash并搜索'test'或'['(撇号是搜索的一部分)，则将找到[的文档.命令，也称为test命令.如果使用man bash而不是info bash，请搜索^ *test(在行首的单词test，后跟一些空格).

Assuming the bash documentation is installed on your system, if you type info bash and search for 'test' or '[' (the apostrophes are part of the search), you'll find the documentation for the [ command, also known as the test command. If you use man bash instead of info bash, search for ^ *test (the word test at the beginning of a line, following some number of spaces).

在引用"Bash条件表达式"之后，您将获得对-ne的描述，这是数字不等式运算符("ne"代表不等于".相反，!=是 string 不等式运算符.

Following the reference to "Bash Conditional Expressions" will lead you to the description of -ne, which is the numeric inequality operator ("ne" stands for "not equal). By contrast, != is the string inequality operator.

您还可以在网上找到bash文档.

You can also find bash documentation on the web.

• Bash参考
• Bourne shell内置程序(包括test和[)
• Bash条件表达式-(滚动到底部； -ne在" arg1 OP arg2 "下)
• test
的POSIX文档

• Bash reference
• Bourne shell builtins (including test and [)
• Bash Conditional Expressions -- (Scroll to the bottom; -ne is under "arg1 OP arg2")
• POSIX documentation for test

test命令的官方定义是POSIX标准(bash实现应相当好地遵循它，也许还会有一些扩展).

The official definition of the test command is the POSIX standard (to which the bash implementation should conform reasonably well, perhaps with some extensions).

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