You could use ps to see the list of processes and filter it for the username. For example, if someone logs on as joeblogs, you could use:
Code:
ps aux | grep '^joeblogs'
You could then use the kill command to kill their shell and any other processes you didn't want running. This requires root access.
A better approach would be to stop them from logging on in the first place or at least limiting what they can run. Who are these remote users?
killing users who logon to server
