Sometimes it can be useful to get notified when someone logs into the system via SSH. This article shows several possible solutions how to configure those notifications.
How to Log Successful SSH Login Attempts
CentOS, wp-cli, and rkhunter
This story was told by my colleague. She had a CentOS 7 server with a bunch of WordPress installations, and she needed to update them all. She obviously did not want to do that manually and preferred to use wp-cli.