Linux下Shell中特殊变量$!,$?,$@,$#,$*的变量说明

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：

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1  1 #!/bin/bash

2  2 #

3  3 printf "The complete list is %s\n" "$$"

4  4 printf "The complete list is %s\n" "$!"

5  5 printf "The complete list is %s\n" "$?"

6  6 printf "The complete list is %s\n" "$*"

7  7 printf "The complete list is %s\n" "$@"

8  8 printf "The complete list is %s\n" "$#"

9  9 printf "The complete list is %s\n" "$0"

10 10 printf "The complete list is %s\n" "$1"

11 11 printf "The complete list is %s\n" "$2"

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结果：

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1[Aric@localhost ~]$ bash params.sh 123456 QQ

2The complete list is 24249

3The complete list is 

4The complete list is 0

5The complete list is 123456 QQ

6The complete list is 123456

7The complete list is QQ

8The complete list is 2

9The complete list is params.sh

10The complete list is 123456

11The complete list is QQ

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