For Oracle Solaris systems that are used as multiuser timesharing systems, you might need to determine if any users are logged into the system before shutting it down. Use the following procedure in these instances.
$ who holly console May 7 07:30 kryten pts/0 May 7 07:35 (starlite) lister pts/1 May 7 07:40 (bluemidget)
Data in the first column identifies the user name of the logged-in user.
Data in the second column identifies the terminal line of the logged-in user.
Data in the third column identifies the date and time that the user logged in.
Data in the fourth column, if present, identifies the host name if the user is logged in from a remote system.