This looks good and I'm sure it was created to scratch a particular itch but a simple approach to this (in bash) is changing the $HISTFILE depending on 'context

This looks good and I'm sure it was created to scratch a particular itch but a simple approach to this (in bash) is changing the $HISTFILE depending on 'context'. I personally have a custom shell function inspired by virtualenvwrapper's 'workon' that sets the stage, so to speak, based on its arguments. One of the things it does is export various env variables including HISTFILE. For me this is a more flexible way to introduce customisation (for instance one of the last thing my function does is look for a project specific function (name of which is env derived) and execute it ...and then it's turtules all the way down )