The Example in the readline documentation (section 6.7 of the Library Reference) shows how to save your readline history in a file, and restore it each time you start Python. The problem with the Example is that it does not include a call to readline.set_history_length and the default is -1 (infinite). As a Python developer, I start Python quite a lot and had a .python_history file that was 850M bytes. Just starting Python was causing my system to thrash before the first prompt (>>>) even appeared. I suggest adding the following line to the example to avoid this: readline.set_history_length(1000) I'm not sure how far back this goes in terms of earlier versions of Python, but probably quite far.
What version of Readline are you using? Is it perhaps Editline (libedit)? When I experimented with Editline on Linux once, I think I saw the history file doubling in size every time I ran Python. Maybe that is what you are seeing.
