shell编程中的$(command)和`command`有什么区别? [英] What is the difference between $(command) and `command` in shell programming?

问题描述

要将命令的输出作为变量存储在sh/ksh/bash中，您可以执行任何一个操作

To store the output of a command as a variable in sh/ksh/bash, you can do either

var=$(command)

或

var=`command`

两种方法之间有什么区别?

What's the difference if any between the two methods?

推荐答案

不推荐使用反引号/刻痕，而推荐使用$()代替命令，因为$()可以像$(echo foo$(echo bar))一样容易地嵌套在其内部.还存在其他差异，例如反引号/标记版本中反斜杠的解析方式等.

The backticks/gravemarks have been deprecated in favor of $() for command substitution because $() can easily nest within itself as in $(echo foo$(echo bar)). There are other differences such as how backslashes are parsed in the backtick/gravemark version, etc.

请参见 BashFAQ/082 ，以始终偏爱以下原因: $(...)语法.

See BashFAQ/082 for several reasons to always prefer the $(...) syntax.

另请参见 POSIX 规范以获取有关各种差异的详细信息.

Also see the POSIX spec for detailed information on the various differences.

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