Whoami
From DikapediaV2
https://www.thegeekstuff.com/2009/03/4-ways-to-identify-who-is-logged-in-on-your-linux-system/
whoami command is used to print the loggedin user name.
$ whoami john
whoami gives the same output as id -un as shown below:
$ id -un john
whoami command will display the logged-in user name and current tty details. The output of this command contains the following columns: logged-in user name, tty name, current time with date and ip-address from where this users initiated the connection.
$ who am i john pts/2 2009-03-28 23:04 (dev-db-server) $ who mom likes john pts/2 2009-03-28 23:04 (dev-db-server) $ who mom hates ec2-user pts/0 2020-06-15 05:43 (ip68-100-237-178.dc.dc.cox.net) $ who -m
saml pts/1 2014-01-06 09:44 (:0)
$ who likes candy saml pts/1 2014-01-06 09:44 (:0) $ who eats cookies saml pts/1 2014-01-06 09:44 (:0) $ who blah blah saml pts/1 2014-01-06 09:44 (:0)
Warning: Don't try "who mom hates" command.
Also, if you do su to some other user, this command will give the information about the logged in user name details.