bash “-ne”在bash中是什么意思？

What does "-ne" mean in bash?

提问by ZenBalance

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

命令“-ne”在 bash 脚本中是什么意思？

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

例如，bash 脚本中的以下行有什么作用？

[ $RESULT -ne 0 ] 

回答by Keith Thompson

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

如果您不知道去哪里寻找，这是很难搜索到的东西之一。

[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.

[实际上是一个命令，而不是您所期望的 bash shell 语法的一部分。它恰好是 Bash 内置命令，因此在 Bash 手册中有记录。

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

还有一个执行相同操作的外部命令；在许多系统上，它由 GNU Coreutils 包提供。

[is equivalent to the testcommand, except that [requires ]as its last argument, and testdoes not.

[等价于test命令，除了[需要]作为它的最后一个参数，而test不是。

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

假设您的系统上安装了 bash 文档，如果您键入info bash并搜索'test'or '['（撇号是搜索的一部分），您将找到该[命令的文档，也称为test命令。如果使用man bash代替info bash，则搜索^ *test（行首的单词test，后跟一定数量的空格）。

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 stringinequality operator.

跟随对“Bash 条件表达式”的引用将引导您了解-ne，它是数字不等式运算符（“ne”代表“不等于”）。相比之下，!=它是字符串不等式运算符。

You can also find bash documentation on the web.

您还可以在网上找到 bash 文档。

• Bash reference
• Bourne shell builtins(including testand [)
• Bash Conditional Expressions-- (Scroll to the bottom; -neis under "arg1OP arg2")
• POSIX documentation for test

• Bash 参考
• Bourne shell 内置函数（包括test和[）
• Bash 条件表达式——（滚动到底部；-ne在“ arg1OP arg2”下）
• POSIX 文档 test

The officialdefinition of the testcommand is the POSIX standard (to which the bash implementation should conform reasonably well, perhaps with some extensions).

该命令的官方定义test是 POSIX 标准（bash 实现应该很好地符合该标准，也许还有一些扩展）。

回答by Omegaman

"not equal" So in this case, $RESULTis tested to not be equal to zero.

“不等于”所以在这种情况下，$RESULT被测试为不等于零。

However, the test is done numerically, not alphabetically:

但是，测试是按数字进行的，而不是按字母顺序进行的：

n1 -ne n2     True if the integers n1 and n2 are not algebraically equal.

compared to:

相比：

s1 != s2      True if the strings s1 and s2 are not identical.