$( )与
(反引号)都是用来做命令替换(command substitution)用的
run command 3, 2, 1
command1 $(command2 $(command3))
${ }用来作变量替换
A=1
echo ${A}0 # print 10
$( )与
(反引号)都是用来做命令替换(command substitution)用的
run command 3, 2, 1
command1 $(command2 $(command3))
${ }用来作变量替换
A=1
echo ${A}0 # print 10