It's okay that there are history files logging the commands that has been used. That't not the problem. The problem is that when 2 admins are logged in to an AIX server then it could be bad:

If admin #A uses

rm FILENAME 

then if admin #B hits the up arrow he gets the

rm FILENAME 

command which is not a very good thing. So how can the termial be forced to only write the command history if the ssh session ended?