I'm not sure I understand the command "uptime"
uptime 13:58 up 5 days, 9:49, 3 users
I have 3 users detected, but I have only one user account on the Mac and no sharing enabled.
What the users actually are?
Every terminal window you have opened counts as a login. Open more terminals and type the command again and you will see how the number changes.
Close Terminal.app, then open one Terminal.app window and read the manual pages for
man uptime, then execute each command e.g.
whoin that order in that one Terminal.app window you opened.
It should become apparent however if not... There are always at least two users logged in, you using
console and note its time, it's corresponds to the time you logged into your account from the GUI, and you using
ttys000 (the Terminal.app windows that you opened). In these instances you is as shown in the output of
who am i.
Each additional Terminal window you open will show as another user using , e.g.
The 'who' command lists logged-in users. You will probably find that they are multiple copies of yourself; one for each terminal window and one for the "console" session.