Log in to the system to be shut down.
The following example shows how to display who is logged in to the system.
$ 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 forth column, if present, identifies the host name if a user is logged in from a remote system.