Update hosts file provided

hosts.sh

#!/usr/bin/env bash
set -e
APP_HOSTS="www1.example.com www2.example.com"
KUBE_IP=127.0.0.1
[[ -f /tmp/hosts.new ]] && rm -f /tmp/hosts.new
for APP_HOST in ${APP_HOSTS}; do
    grep "$APP_HOST" /etc/hosts | while read FOUND; do
        if [[ ${FOUND} == "$KUBE_IP $APP_HOST" ]]; then
            echo "=== $FOUND"
        else
            [[ -f /tmp/hosts.new ]] || cp -f /etc/hosts /tmp/hosts.new
            echo "--- $FOUND"
            grep -v "$FOUND" /tmp/hosts.new > /tmp/hosts.tmp && mv -f /tmp/hosts.tmp /tmp/hosts.new
        fi
    done
    if [[ ! $(grep "$KUBE_IP $APP_HOST" /etc/hosts) ]]; then
        echo "+++ $KUBE_IP $APP_HOST"
        echo "$KUBE_IP $APP_HOST" >> /tmp/hosts.new
    fi
done
[[ -f /tmp/hosts.new ]] && sudo -- sh -c -e "cp -f /etc/hosts /etc/hosts.bak && mv -f /tmp/hosts.new /etc/hosts"