I face this issue on some of Unix servers. When I open different session for same user, command history is shared by all the session. This creates issues if by mistake I press
up arrow and just press Enter.
On one occasion I end up running
rm -rf * thankfully I was in directory where I don't have permissions to remove files.
How to have separate command history for different sessions for the same user? Most of the time I am using ksh and tcsh shells.