ip_update.sh

#!/bin/bash
#This one mails you the ip if it changes
#Deuteu inspired and guided by Allegrem

#Env variables
path="/home/user/ip_script"
old="$path/ip_old.dat"
mail="$path/ip_mail.txt"
log="$path/ip_log.log"

#IP
T1=`curl -s icanhazip.com`
#curl ipinfo.io/ip #IPv4
#curl ifconfig.me #IPv4
#curl -s icanhazip.com #IPv6
read T2 < $old

#Mail variables
from="sender@gmail.com"
to="example@domain.com"
head="From: $from
To: $to
Subject: IP Adress
"
body="Computer IP is: $T1"

echo "$head" > $mail
date >> $mail
echo "$body" >> $mail


if [ "$T1" = "" ]; then
    echo "[`date`] - [ip_update] - IP couldn't be retrieve - doing nothing" >> $log
elif [ "$T1" = "$T2" ]; then
    echo "[`date`] - [ip_update] - IP is the same: $T1 - doing nothing " >> $log
else
    echo "[`date`] - [ip_update] - IP has changed: $T1 - send mail" >> $log
    /usr/sbin/sendmail example@domain.com < $mail
    echo "$T1" > $old
fi