shell脚本注释指定文件的指定行

[root@node20 data]# vim zhushi.sh 

#!/bin/bash
#By:Platowg 
#Date:2019.01.15
echo "若是只注释一行，请数据相同的数字"
read -p "请输入须要注释的行开始行号:" num1
read -p "请输入须要注释的行结束行号:" num2
if [ $num2 -ge $num1 ] >/dev/null 2>&1;then
        echo "开始执行注释操做"
else
        echo -e "\e[31m输入错误,请输入正整数\e[0m";exit
fi
file=/etc/hosts
if [ "$num1" ] && [ "$num2" ];then
        sed -i "${num1},${num2}s/^/#/" $file
        echo -e "\e[33mok\e[0m"
else
        echo -e "\e[31mno\e[0m"
fi