How do I exit python in the Mountain Lion Terminal? I'm having a couple problems with basic command line stuff in the terminal of Mountain Lion.

control + D does not exit Python as it does in Lion; instead it splits the screen.

Meanwhile, I also haven't figured out how to continue writing after having viewed the contents of a text document - the terminal doesn't allow it.

Hello hello hello!
ex12.txt (END)


So far, no matter what I push after this, I get a nasty little beeping sound
As Control + D works for me on multiple Macs, I'll presume something is amiss with your installation, keyboard or keyboard handler. (Your difficulty with the pager also lends credence to this theory.) 

You can use the alternate quit() to exit the interpreter until you have looked at how Python was installed or think of some modifications you might have on the key mapping on your Mac.