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：

[Aric@localhost ~]$ bash params.sh 123456 QQ
The complete list is 24249
The complete list is
The complete list is 0
The complete list is 123456 QQ
The complete list is 123456
The complete list is QQ
The complete list is 2
The complete list is params.sh
The complete list is 123456
The complete list is QQ