Cloudflare API v4 Dynamic DNS Update in Bash

cloudflare-update-record.sh

#!/bin/bash

# CHANGE THESE
auth_email="[email protected]"
auth_key="c2547eb745079dac9320b638f5e225cf483cc5cfdda41" # found in cloudflare account settings
zone_name="example.com"
record_name="www.example.com"

# MAYBE CHANGE THESE
ip=$(curl -s http://ipv4.icanhazip.com)
ip_file="ip.txt"
log_file="cloudflare.log"

# SCRIPT START
echo "[$(date)] - Check Initiated" >> $log_file

if [ -f $ip_file ]; then
        old_ip=$(cat $ip_file)
        if [ $ip == $old_ip ]; then
                echo "IP has not changed."
                exit 0
        fi
fi

zone_identifier=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones?name=$zone_name" -H "X-Auth-Email: $auth_email" -H "X-Auth-Key: $auth_key" -H "Content-Type: application/json" | grep -Po '(?<="id":")[^"]*' | head -1 )

record_identifier=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_identifier/dns_records?name=$record_name" -H "X-Auth-Email: $auth_email" -H "X-Auth-Key: $auth_key" -H "Content-Type: application/json"  | grep -Po '(?<="id":")[^"]*')

update=$(curl -s -X PUT "https://api.cloudflare.com/client/v4/zones/$zone_identifier/dns_records/$record_identifier" -H "X-Auth-Email: $auth_email" -H "X-Auth-Key: $auth_key" -H "Content-Type: application/json" --data "{\"id\":\"$zone_identifier\",\"type\":\"A\",\"name\":\"$record_name\",\"content\":\"$ip\"}")

if [[ $update == *"\"success\":false"* ]]; then
    echo "[$(date)] - API UPDATE FAILED. DUMPING RESULTS:" >> $log_file
    echo "$update" >> $log_file
    echo "API UPDATE FAILED. DUMPING RESULTS:"
    echo "$update"
else
    echo "$ip" > $ip_file
    echo "[$(date)] - IP changed to: $ip" >> $log_file
    echo "IP changed to: $ip"
fi