Apple Remote Desktop 2: Send UNIX Command fails when target computer is at the login window

To use the Send UNIX Command, either a local user must be logged in to the client computer, or you must execute the command as a specific local user.

Otherwise, you will get this message:

"This task will fail. A console user is not logged in on <your server>."

To avoid this, run the UNIX command as the currently logged in user, or run it as a particular user on the client computer, such as root or <any_username>. The latter method is the only way to run a UNIX command when the target is at the login window.