Check who is logged in - Windows

WMIC

This command will return the name of the user who is currently logged into the console.
Note: It does not return the names of users who are connected via RDP.

WMIC /NODE: "workstation_name" COMPUTERSYSTEM GET USERNAME

Command Line

To see a list of remote connected users run this command:

qwinsta

or for a list of remote connected users on another server:

qwinsta /server:<SERVER_HOSTNAME>

Where <SERVER_HOSTNAME> is the hostname of the server you want to check.