this page will show you what command you can use in linux to show you who is trying to login to your server and who is logging in whether it failed or it was successful it will show you a log of who is trying to access your linux server either through ssh or through the terminal.

finding out is very easy, all you have to do is use the command last to show you who are the last users who either tried but failed to login or who successfully logged in. try it.

good luck

linux command: