How do I add global code?

I'm trying to figure out how to make inputs global, so if I was in another program I could say use it. For ex: I make a program in which my password = pie, in another program I want to login with that, how do I bring it over without copying the code?

anything you define without the local keyword is in the global space.

foo = "bar" --# global space
local bar = "foo" --# local/program space

Also do you know how to constantly have a program running while also being able to say edit other programs?

The coding is complex, but if you have ComputerCraft 1.6 or later, that provides a pre-made script for doing so called multishell.

If you don't have 1.6, then I'd recommend just placing down a second computer.