Bash IF 条件中的感叹号是否代表否定？

Question

我看到了一些类似

的东西

if ! some-command; then
    #do something
fi

感叹号有什么作用？我看到如果你使用括号，it can be used for negation。

这里也是一样的效果吗？

Answer 1

如 man bash 中所述：

If the reserved word ! precedes a pipeline, the exit status of that pipeline is the logical negation of the exit status as described above.

Answer 2

正确。

这是一个代码示例：

anny ~> if ! grep $USER /etc/passwd
More input> then echo "your user account is not managed locally"; fi
your user account is not managed locally

anny > echo $?
0

anny >

来源：http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_07_01.html

Bash IF 条件中的感叹号是否代表否定？

Does the Exclamation point represent negation in Bash IF condition?

bash

conditional

if-statement