My Bash script won't cache an item - bash

Question

I'm trying to use a Bash script I found and have slightly modified to automatically update the DNS settings on GoDaddy.
It sort of works, however I'm not getting the echo "no ip address, program exit" because I don't think on line 28 the cache file is being created. Would anybody be able to tell me what's going on? I'm using Raspbian. Many thanks in advance!
#/bin/bash
# This script is used to check and update your GoDaddy DNS server to the IP address of your current internet connection.
#
# Original PowerShell script by mfox: https://github.com/markafox/GoDaddy_Powershell_DDNS
# Ported to bash by sanctus
# Added AAAA record by Binny Chan
#
# Improved to take command line arguments and output information for log files by pollito
#
# First go to GoDaddy developer site to create a developer account and get your key and secret
#
# https://developer.godaddy.com/getstarted
#
# Be aware that there are 2 types of key and secret - one for the test server and one for the production server
# Get a key and secret for the production server
# Check an A record and a domain are both specified on the command line.
if [ $# -ne 2 ]; then
echo "usage: $0 type a_record domain_name"
echo "usage: $0 AAAA www my_domain"
exit 1
fi
# Set A record and domain to values specified by user
name=$1 # name of A record to update
domain=$2 # name of domain to update
cache=/tmp/.mcsync.$name.$domain.addr
[ -e $cache ] && old=`cat $cache`
# Modify the next two lines with your key and secret
key="key" # key for godaddy developer API
secret="secret" # secret for godaddy developer API
headers="Authorization: sso-key $key:$secret"
#echo $headers
# Get public ip address there are several websites that can do this.
ret=$(curl -s GET "http://ipinfo.io/json")
currentIp=$(echo $ret | grep -oE "\b([0-9]{1,3}\.){3}[0-9]{1,3}\b")
# Check empty ip address or not
if [ -z "$currentIp" ]; then
echo $name"."$domain": $(date): no ip address, program exit"
exit 1
fi
# Check cache ip, if matched, program exit
if [ "$old" = "$currentIp" ]; then
echo $name"."$domain": $(date): address unchanged, program exit $currentIp"
echo "IPs equal. Exiting..."
exit
else
echo $name"."$domain": $(date): currentIp:" $currentIp
fi
#Get dns ip
result=$(curl -s -k -X GET -H "$headers" \
"https://api.godaddy.com/v1/domains/$domain/records/A/$name")
dnsIp=$(echo $result | grep -oE "\b([0-9]{1,3}\.){3}[0-9]{1,3}\b")
echo $name"."$domain": $(date): dnsIp:" $dnsIp
# ip not match
if [ "$dnsIp" != $currentIp ];
then
echo $name"."$domain": $(date): IPs not equal. Updating."
request='{"data":"'$currentIp'","ttl":3600}'
#echo $request
nresult=$(curl -i -k -s -X PUT \
-H "$headers" \
-H "Content-Type: application/json" \
-d $request "https://api.godaddy.com/v1/domains/$domain/records/A/$name")
#echo $nresult
echo $name"."$domain": $(date): IPs not equal. Updated."
fi

Answer 1

No, the message is on line 44, which is written because $currentIp is empty, which is retrieved on line 39: reading the response of curl request to "http://ipinfo.io/json".
otherwise just remove the cache file
rm /tmp/.mcsync.$name.$domain.addr
where $name and $domain are replaced with first and second argument to script.