Instead of using a cronjob placed in our crontab, we can make use of a systemd timer on a modern linux system which is running systemd.
For a systemd timer to work, it needs two parts.
One part consists of a
.timer file, and a
.timer file specifies when our service should be started. Just like a cronjob we can specify here on which days, in which week or at which time our service should be started.
.service file contains all the details about the script or command we want to run.
With the following script we monitor the SSH login on a server and send a notification via Telegram API.
This way you will get a notification in real time when someone logs in to your server via SSH. For me this is a valuable security feature.