How do I access the command history from IDLE?

just use Alt+P to go up. Similarly, Alt+N could be used to go down.

If you're on mac, it's ctrl+p.

• I think you are looking for the history-previous action, which is bound to Alt+P by default.
• You can remap it in "Options -> Configure IDLE -> Keys"
• You can also access this command from the top menu in IDLE: "Shell -> Previous History"

Incidentally, why don't you try a better (less ugly, for starters) shell like bpython or ipython?

Go into Preferences > Keys. Find the 'history-previous' selection in the list and edit it to Up Arrow.