Here is a good article on how to manage your shell history. For those of you that don’t know, all the commands that you enter into a Bash shell (default shell on many Linux distros) are stored in a history file. This is to allow a user to use previous executed commands. The problem with this is that an attacker could easily compromise this history file and get all kinds of good data if they were able to own your machine. With these tips you can limit the size and behaviour of this file or remove the history on logout.