Bash中的$符号

脚本名称：$0

PID：$$

参数个数：$#

脚本返回值：$?

第x个参数：$x

第10个以上的参数加大括号：${10}

所有参数：$@

 #!/bin/bash
 echo "The program $0 is now running"
 echo "The progress PID is $$"
 echo "The last progress PID is $$"
 echo "The number of parameter is $# "
 echo "The return code of last command is $?"
 echo "The first parameter is $1"
 echo "The second parameter is $2"
 echo "The parameters are: $*"
 echo "Again, the parameters are: $@"