shell 练习-用户交互脚本

while :
do
        read -p "Please input a number:(end for exit) " n
        num=` echo $n |sed -r 's/[0-9]//g'|wc -c `
        if [ $n == "end" ]
                then
                        exit
                elif [ $num -ne 1  ]
                        then
                        echo "what you input is not a number!Try again!"
                else
                        echo "your input number is: $n"
        fi
done