shell之case

#!/bin/sh

echo "It is morning? Please answer yes or no"
read timeofday
case "$timeofday" in
    yes | y | Yes | YES)//正则表达式
        echo "Good morning"
        echo "Up bright and early this morning"
        ;;
    [nN]*)
        echo "Good Afternoon"
        ;;
    *)
        echo "Sorry,answer not recognized"
        echo "Please answer yes or no"
        exit 1
        ;;
esac

exit 0

为了让case的匹配功能更强大，我们可以用如下的模式：

 [yY] | [Yy][Ee][Ss])