什么是$（命令），并在shell编程`command`之间的区别？
问题描述：
在SH / KSH / bash中存储一个命令的输出，你可以做一个变量为
In sh/ksh/bash to store the output of a command as a variable you can do either
MY_VAR=$(command)
#or you can do
MY_VAR=`command`
有什么区别，如果这两种方法之间的？
What's the difference if any between the two methods?
答
反引号/ gravemarks已经去赞成 $（）的pcated为命令替换$ P $因为 $（）可以在自己方便地窝在 $（foo的回声$（回声酒吧））。另外还有诸如如何反斜杠的反引号/ gravemark版本被解析细微的差别。
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 also minor differences such as how backslashes are parsed in the backtick/gravemark version.
查看POSIX SPEC上的各种差异的详细信息。
See the POSIX spec for detailed information on the various differences.