Someone asked at the mailing list of my local LUG if there is any way of learning the last command issued on a GNU/Linux system.
We're talking last command in a system-wide fashion I guess. After reasoning for a while if you limit the set of commands to the ones issued by actual users using an interactive console then the last one should have been registered in the command history.
Another way of thinking of this question would be asking how to tell which was the last processed that was created on a GNU/Linux box regarding if it's still running or has already finished executing, which was the parent processes and other relevant information.