Bash script to update Cloudflare DNS record. step 1: sudo chmod +x cloudflare.sh step2: */10 * * * * /bin/bash ~/cloudflare.sh

cloudflare.sh

#!/bin/bash

auth_email="someone@gmail.com" # The email used to login 'https://dash.cloudflare.com'
auth_key="your Global API Key" # Top right corner, "My profile" > "Global API Key"
zone_identifier="your domain's Zone ID" # Can be found in the "Overview" tab of your domain
record_name="test.example.com" # Which record you want to be synced
proxy=false # Set the proxy to true or false


###########################################
## Check if we have a public IP
###########################################
ip=$(curl -s https://ipv4.icanhazip.com/ || curl -s https://api.ipify.org)
if [ "${ip}" == "" ]; then
  message="No public IP found."
  >&2 echo -e "${message}" >> ~/log
  exit 1
fi

###########################################
## Seek for the A record
###########################################
echo " Check Initiated" >> ~/log
record=$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/$zone_identifier/dns_records?name=$record_name" -H "X-Auth-Email: $auth_email" -H "X-Auth-Key: $auth_key" -H "Content-Type: application/json")

###########################################
## Set the record identifier from result
###########################################
record_identifier=$(echo "$record" | grep -Po '(?<="id":")[^"]*' | head -1)

###########################################
## Change the IP@Cloudflare using the API
###########################################
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: $auth_key" -H "Content-Type: application/json" --data "{\"type\":\"A\",\"proxied\":${proxy},\"name\":\"$record_name\",\"content\":\"$ip\"}")

###########################################
## Report the status
###########################################
case "$update" in
*""success":false"*)
  message="$ip $record_name DDNS failed for $record_identifier ($ip). DUMPING RESULTS:n$update"
  >&2 echo -e "${message}" >> ~/log
  exit 1;;
*)
  message="$ip $record_name DDNS updated."
  echo "${message}" >> ~/log
  exit 0;;
esac