linux中shell变量$#,$@,$0,$1,$2的含义解释

Posted 2020-06-19 my_cool2007

摘抄自：ABS_GUIDE

下载地址：http://www.tldp.org/LDP/abs/abs-guide.pdf

linux中shell变量$#,[email protected],$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。  [email protected]  所有参数列表。如"[email protected]"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：

1 #!/bin/bash  2 #  3 printf "The complete list is %s\n" "$$"  4 printf "The complete list is %s\n" "$!"  5 printf "The complete list is %s\n" "$?"  6 printf "The complete list is %s\n" "$*"  7 printf "The complete list is %s\n" "[email protected]"  8 printf "The complete list is %s\n" "$#"  9 printf "The complete list is %s\n" "$0" 10 printf "The complete list is %s\n" "$1" 11 printf "The complete list is %s\n" "$2

结果：

[[email protected] ~]$ 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