linux中shell变量$#,$@,$0,$1,$2的含义解释

linux中shell变量$#,$@,$0,$1,$2的含义解释:
变量说明:
$$
Shell本身的PID（ProcessID）
$!
Shell最后运行的后台Process的PID
$?
最后运行的命令的结束代码（返回值）
$-
使用Set命令设定的Flag一览
$*
所有参数列表。如”$*”用「”」括起来的情况、以”$1 $2 … $n”的形式输出所有参数。
$@
所有参数列表。如”$@”用「”」括起来的情况、以”$1” “$2” … “$n” 的形式输出所有参数。
$#
添加到Shell的参数个数
$0
Shell本身的文件名
$1～$n
添加到Shell的各参数值。$1是第1参数、$2是第2参数…。
示例：

  #!/bin/bash
  printf "The complete list is %s\n" "$$"
  printf "The complete list is %s\n" "$!"
  printf "The complete list is %s\n" "$?"
  printf "The complete list is %s\n" "$*"
  printf "The complete list is %s\n" "$@"
  printf "The complete list is %s\n" "$#"
  printf "The complete list is %s\n" "$0"
  printf "The complete list is %s\n" "$1"
  printf "The complete list is %s\n" "$2

结果：

[dirk@localhost ~]$ bash params.sh dirk  2014
The complete list is 21236
The complete list is
The complete list is 0
The complete list is dirk 2014
The complete list is dirk
The complete list is 2014
The complete list is 2
The complete list is params.sh
The complete list is dirk
The complete list is 2014