Print the names of all logged-in users on the current host.
users [OPTION]... [FILE]
--help Display help information and exit.
--version Display version information and exit.
FILE (optional): A file that records the user's current login status; /var/run/utmp
and /var/log/wtmp
are used by default.
Returning 0 indicates success, returning a non-zero value indicates failure.
[root@localhost ~]# users
root root