Print the user names of users currently logged in to the current host.
users [OPTION]... [FILE]
--help Display help information and exit.
--version Display version information and exit.
FILE (optional): The file that records current user logins; defaults to /var/run/utmp and /var/log/wtmp.
Returns 0 on success, and a non-zero value on failure.
[root@localhost ~]# users
root root
GNU coreutils package. For related help information, please see man -s 1 users or info coreutils 'users invocation'.