case $变量名 in
    "值1")
        如果变量的值等于值1，则执行程序1， 
        ；；
    "值2")
        如果变量的值等于值2，则执行程序，
        ；；
      ：：
    *)
        如果变量的值都不是以上值，则执行此程序
        ；；
esac

#!/bin/bash
echo "you want to shanghai , please input 1 "
echo "you want to guangzhou , please input 2 "
echo "you want to chengdu ,  please input 3"
read -t 30 -p "Please input your chooise : " cho
case "$cho" in
  "1")
    echo "shanghai is jipiao fashou!"
    ;;
  "2")
    echo "guangzhou!"
    ;;
  "3")
    echo "chengdu!"
    ;;
  *)
    echo "chengdu!"
    ;;
esac