> btw, is the shell variable for no history same for bash and csh?
No. What I said before about "savehist" only applies to csh/tcsh. The
following applies to bash:
HISTFILE
The name of the file in which command history is saved.
(See HISTORY below.) The default value is
~/.bash_history. If unset, the command history is not
saved when an interactive shell exits.
Shawn