Shell 编程基础之 Select 练习

一、语法

select 变量 in con1 con2 con3    # 自动列出 con1，con2，con3 的选择菜单
do
    #执行内容
break    # select本身就是一个循环，break是当选择后，就跳出循环
done

二、练习

1. select + case 模拟 Linux 启动脚本
   

   function programstatus(){
     if [ "$1" -eq 0 ]; then
       echo "* program is running"
     else
       echo "* program has stopped"
     fi
   }
   
   status=0 #0: start; 1:stop
   select p in "start" "stop" "status" "restart" "*" ""
   do
   case "$p" in
   "start")
     status=0
     programstatus $status
     ;;
   "stop")
     status=1
     programstatus $status
     ;;
   "status")
     programstatus $status
     ;;
   "restart")
     if [ "$status" -eq 0 ]; then
       status=1
       echo "* program has stopped"
     fi
     status=0
     echo "* program is running"
     ;;
   "")
     break
     ;;
   *)
     echo "Plz input [start|stop|status|restart]"
      ;;
   esac
   done

   user@ae01:~$ ./test.sh
   1) start
   2) stop
   3) status
   4) restart
   5)
   #? 1
   * program is running
   #? 2
   * program has stopped
   #? 3
   * program has stopped
   #? 4
   * program is running
   #? 5
   user@ae01:~$