What is in your eyes 'the currently logged in user'? If you want the account used to log in to the Mac, you can use "ls -l /dev/console | awk '/ / { print $3 }'" to get the account. If you want to know the account that was used to login to the Self-Service, you can use "$3" to get the account. In many environments both might be the same, in some environments they can be different. In our place most users use local accounts to log in to their Mac, but Active Directory accounts to log in the Self-Service, so for use "$3" would not work.
