Need an EXE to get client-name in Windows 2008

I need a realy simple task: an exe that will run in command line, and will return the client-name of current user, in Windows 2008 (R2, E3). The client name is shown in task managers/users in the right column. I need that the output will be written in txt file. The name and path of the output file will be parameters. Can you do it? S