typora/note/Shell/case 语法.md

语法结构

• 多重匹配语句
• 如果匹配成功，执行相匹配的命令

pattern 表示需要匹配的模式

case var in
pattern 1)  # 可以用 | 分割多个模式，相当于 or 
	command 1 # 需要执行的语句
	;;        # 两个分号代表命令结束
pattern 2)
	command 2
	;;
					*) # default 不满足以上模式，默认执行下边的语句
	command 3
	;;
esac 

#! /bin/env bash

case $1 in
	start|S)
		echo "service starting"
		;;
	stop|T)
		echo "service stopping"
		;;
	reload|R)
		echo "service restarting"
		;;
	*)
		echo "invalid params: $1"
		;;
esac

me@me-EQ59:~/shell_demo/scripts/shell03$ ./case_1.sh
invalid params:
me@me-EQ59:~/shell_demo/scripts/shell03$ ./case_1.sh 2
invalid params: 2
me@me-EQ59:~/shell_demo/scripts/shell03$ ./case_1.sh start
service starting
me@me-EQ59:~/shell_demo/scripts/shell03$ ./case_1.sh S
service starting
me@me-EQ59:~/shell_demo/scripts/shell03$ ./case_1.sh reload
service restarting
me@me-EQ59:~/shell_demo/scripts/shell03$ ./case_1.sh T
service stopping
me@me-EQ59:~/shell_demo/scripts/shell03$