Add History and Tab Completion to the Default Python Shell

So I've in the python shell quite a bit lately and figured it would be nice to be able to have readline history between sessions as well as tab completion. Yes I know things like iPython exist as well as others but wanted to keep it simple. It turns out its not that hard to enable and here is how you do it.

First you'll need to add a line to your .bashrc or .profile setting your PYTHONSTARTUP environment variable

# ~/.bashrc
export PYTHONSTARTUP=$HOME/.pythonstartup.py

Then copy this scripts contents to file your new environment variable points to

# ~/.pythonstartup.py
try:
    import readline
    import rlcompleter
    import atexit
    import os
except ImportError:
    print "Python shell enhancement modules not available."
else:
    histfile = os.path.join(os.environ["HOME"], ".pythonhistory")
    import rlcompleter
    readline.parse_and_bind("tab: complete")
    if os.path.isfile(histfile):
        readline.read_history_file(histfile)
    atexit.register(readline.write_history_file, histfile)
    del os, histfile, readline, rlcompleter, atexit
    print "Python shell history and tab completion are enabled."

That's it. Now anytime you pop into the python shell you'll have history from previous sessions as well as tab completion. Enjoy!

Edit: If you're not running the latest version of OSX you may need to change the readline.pasre_and_bind line to the following

#readline.parse_and_bind("tab: complete")
readline.parse_and_bind("bind ^I rl_complete")