A Bash script to notify user if Raspberry Pi's IP address has changed via Telegram.
This script sends messages via Telegram, so you will need a Telegram bot and the recipient's chat ID. Replace <TOKEN> and <CHAT_ID> in the script with the corresponding values.
You can create a new entry in crontab to run the script at specific times. First open crontab: crontab -e.
Then add the following line to the end of the file to run the script hourly: @hourly /path/to/script/ip_checker.sh.
You can change @hourly to a value that you want.
The script generates a file called last_ip.txt in the same directory as the script to store the last IP address. It then checks hourly: if the current IP address is not the same as the last IP address (in last_ip.txt file), it updates the file and sends a message (containing the new IP) to specified user via Telegram.
This script is based on Daniel Lombardi's Home IP Checker, which is written in Python. I took it as reference and rewrite in Bash. My version is more simple and has less functionality because I just wanted to suit my needs.