simple ddns script for cloudflare

ddns.sh

#!/usr/bin/env bash

set -e

CF_TOKEN="********************************"
CF_ZONEID="*************************"

while true
do
    sleep 10

    CURRENT_IP=$(ip addr show dev ppp0 | sed -e's/^.*inet \([^ ]*\) .*$/\1/;t;d' | head -1)
    CURRENT_IP6=$(ip addr show dev ppp0 | grep global | sed -e's/^.*inet6 \([^ ]*\)\/.*$/\1/;t;d' | head -1)
    PREVIOUS_IP=$(cat /tmp/ddns 2>&1 || true)
    PREVIOUS_IP6=$(cat /tmp/ddns6 2>&1 || true)

    # ipv4
    if [ -e "$CURRENT_IP" ]; then
        echo "ERROR: current address not found!"
    elif ! [ "$CURRENT_IP" = "$PREVIOUS_IP" ]; then
        CF_RECORD_ID="*************************"
        CF_RECORD="********************"

        echo "Send new ipv4 address to CloudFlare..."

        CF_RESULT=$(curl -sSL -X PUT https://api.cloudflare.com/client/v4/zones/$CF_ZONEID/dns_records/$CF_RECORD_ID \
        -H 'Content-Type: application/json' \
        -H 'Authorization: Bearer '$CF_TOKEN \
        -d '{"type": "A", "name": "'$CF_RECORD'", "content": "'$CURRENT_IP'", "proxied": false, "ttl": 120}')

        if echo $CF_RESULT | grep '"success": true' > /dev/null; then
            echo $CURRENT_IP > /tmp/ddns
        else
            echo $CF_RESULT
        fi
    fi

    # ipv6
    if [ -e "$CURRENT_IP6" ]; then
        echo "ERROR: current address not found!"
    elif ! [ "$CURRENT_IP6" = "$PREVIOUS_IP6" ]; then
        CF_RECORD_ID="*************************"
        CF_RECORD="*************************"

        echo "Send new ipv6 address to CloudFlare..."

        CF_RESULT=$(curl -sSL -X PUT https://api.cloudflare.com/client/v4/zones/$CF_ZONEID/dns_records/$CF_RECORD_ID \
        -H 'Content-Type: application/json' \
        -H 'Authorization: Bearer '$CF_TOKEN \
        -d '{"type": "AAAA", "name": "'$CF_RECORD'", "content": "'$CURRENT_IP6'", "proxied": false, "ttl": 120}')

        if echo $CF_RESULT | grep '"success": true' > /dev/null; then
            echo $CURRENT_IP6 > /tmp/ddns6
        else
            echo $CF_RESULT
        fi
    fi
done