DNSimple dynamic IP update script

dns.sh

#!/bin/bash
#
# Update DNSimple DNS record if ISP IP changes
#
# Requirements:
#  existing DNS record hosted with DNSimple
#  curl in $PATH
#
# run from cron
#
# e.g. 
# */5 * * * * /home/user/scripts/dns.sh 2&>1 > /dev/null

DNSIMPLE_ACCOUNT_ID=12345
DNSIMPLE_DOMAIN_NAME='example.org'
DNSIMPLE_RECORD_ID=12345678
DNSIMPLE_API_TOKEN='redacted'
IP_FILE='/home/user/scripts/IP'
LAST_IP=$(cat ${IP_FILE})
CURRENT_IP=$(curl -s ipinfo.io/ip)
JSON="{\"content\":\"${CURRENT_IP}\"}"

if [ "$LAST_IP" == "$CURRENT_IP" ]
then
  # IP is the same, don't do anything
  echo $LAST_IP
  echo "IP hasn't changed"
else
  # IP has changed, update DNSimple and re-write IP file
  echo "IP has changed... updating IP"

  curl  -H "Authorization: Bearer ${DNSIMPLE_API_TOKEN}" \
        -H "Accept: application/json" \
        -H "Content-Type: application/json" \
        -X PATCH \
        -d "${JSON}" \
        https://api.dnsimple.com/v2/${DNSIMPLE_ACCOUNT_ID}/zones/${DNSIMPLE_DOMAIN_NAME}/records/${DNSIMPLE_RECORD_ID}

  # update current IP address file
  echo $CURRENT_IP > ${IP_FILE}
fi