script_redirect.sh

echo "Usage sudo redirect.sh http_port https_port"

http_port=$1
https_port=$2
re='^[0-9]+$'

if ! [[ $http_port =~ $re ]] ; then
   echo "error: HTTP PORT Not a number" >&2; exit 1
fi
if ! [[ $https_port =~ $re ]] ; then
   echo "error: HTTPs PORT Not a number" >&2; exit 1
fi

echo "HTTP PORT 80 GOING TO -> "$http_port
echo "HTTPS PORT 443 GOING TO -> "$https_port


read -p "Are you sure? " -n 1 -r
echo    # (optional) move to a new line
if [[ $REPLY =~ ^[Yy]$ ]]
then
    echo "Commiting change!!"
    # do dangerous stuff
    iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 443 -j REDIRECT --to-port $https_port
    iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port $http_port
    iptables -t nat -L
else
    echo "Better Safe than sorry :)"
fi