http://www.linuxfromscratch.org/blfs/view/6.3/postlfs/profile.html
some other pointers:
- $HISTIGNORE environment variable allows you to define a set of commonly used commands that you don't want cluttering up your history list. You can even use RegEx to define the commands you don't are for.
- $HISTCONTROL=ignoreboth is a handy one too so your history file doesn't get any dups