IPv4 / IPv6 address change monitoring and notification bash script with Pushover.net notifications, for use with crontab

pushover-ipchange-watchdog.sh

#!/bin/bash

## IPv4 / IPv6 address change monitoring and notification bash script with Pushover.net notifications 
## intended for use with crontab

if [ ! -e ~/ipv4addr.log ] ; then 
	touch ~/ipv4addr.log
fi

if [ ! -e ~/ipv6addr.log ] ; then 
	touch ~/ipv6addr.log
fi

currentIPv4=$(cat ~/ipv4addr.log)
grabbedIPv4=$(wget -O - -q -nv --delete-after myipv4.addr.tools)

currentIPv6=$(cat ~/ipv6addr.log)
grabbedIPv6=$(wget -O - -q -nv --delete-after myipv6.addr.tools)

# API keys from pushover.net
PUSHOVER_APP_KEY=[your-application-key]
PUSHOVER_USER_KEY=[your-user-key]

# Test push commandline for testing format changes (uncomment lines for use)
#curl -d token=$PUSHOVER_APP_KEY -d user=$PUSHOVER_USER_KEY -d title="IP Address Change" -d timestamp="$(date +%s)" \
#	-d message="[Test push] As of $(date +%c): IP address has changed from [ $currentIPv4 ] to [ $grabbedIPv4 ]" \
#	https://api.pushover.net/1/messages.json 

if [ "$currentIPv4" != "$grabbedIPv4" ] ;
then
	curl -d token=$PUSHOVER_APP_KEY -d user=$PUSHOVER_USER_KEY -d title="IP Address Change" -d timestamp="$(date +%s)" \
		-d message="As of $(date +%c): IP address has changed from [ $currentIPv4 ] to [ $grabbedIPv4 ]" \
		https://api.pushover.net/1/messages.json 
	echo $grabbedIPv4 > ~/ipv4addr.log
fi

if [ "$currentIPv6" != "$grabbedIPv6" ] ;
then
	curl -d token=$PUSHOVER_APP_KEY -d user=$PUSHOVER_USER_KEY -d title="IP Address Change" -d timestamp="$(date +%s)" \
		-d message="As of $(date +%c): IP address has changed from [ $currentIPv6 ] to [ $grabbedIPv6 ]" \
		https://api.pushover.net/1/messages.json 
	echo $grabbedIPv6 > ~/ipv6addr.log
fi