Script to check external ip and send to mail

Maybe it's useful for somebody.
Checks ip and sends to your email., if it has changed. Save as ipcheck.sh and put on /home/USER/
To check every hour, execute crontab -e and add this to the end:

0 * * * * sh ipcheck.sh

Here it goes:

#!/bin/sh

#########################
## uncomment and edit as needed
#########################
#mail_to="email@sapo.pt"
#mail_from="email@sapo.pt"
#user="email@sapo.pt"
#pass="password123"
#host_params="--host=smtp.sapo.pt --port=587 --tls=on --tls-starttls=on --auth=on"

#########################
## do not edit lines bellow
#########################
ip_old=""
ip_new=""
if [ -f ip.txt ]; then ip_old="$(cat ip.txt)";  fi
ip_new="$(curl --connect-timeout 10 --max-time 10 --retry 3 --retry-delay 0 -s icanhazip.com)"

if [ "$ip_new" != "" ] && [ "$ip_new" != "$ip_old" ]
then
echo $ip_new > ip.txt
printf "To:$mail_to\nSubject: IP\n\nOld ip = $ip_old\nNew ip = $ip_new" | msmtp --timeout=10 -t --from=$mail_from --user=$user --passwordeval="echo '$pass'" $host_params
fi