Update AWS Route 53 DNS entry with current IP

gistfile1.txt

#!/bin/sh -e
HOSTED_ZONE_IP=/hostedzone/CHANGEME
DOMAIN=CHANGEME
TTL=300

my_ip=$HOME/.my_ip
IP=$(dig +short myip.opendns.com @resolver1.opendns.com)
if [ "$IP" = "$(cat $my_ip)" ]
then
    exit 0
fi

json=$(cat <<EOF
{
    "Changes": [
        {
            "Action": "UPSERT",
            "ResourceRecordSet": {
                "Name": "$DOMAIN",
                "Type": "A",
                "TTL": $TTL,
                "ResourceRecords": [
                    {
                        "Value": "$IP"
                    }
                ]
            }
        }
    ]
}
EOF
)

aws route53 change-resource-record-sets --hosted-zone-id $HOSTED_ZONE_IP --change-batch "$json"
echo "$IP" > $my_ip