Learning Python, 5th Edition

Appendix A. Installation and Configuration

This appendix provides additional installation and configuration details as a resource for people new to these topics. It’s located here because not all readers will need to deal with these subjects up front. Because it covers some peripheral topics such as environment variables and command-line arguments, though, this material probably merits at least a quick scan for most readers.

Installing the Python Interpreter

Because you need the Python interpreter to run Python scripts, the first step in using Python is usually installing Python. Unless one is already available on your machine, you’ll need to fetch, install, and possibly configure a recent version of Python on your computer. You’ll only need to do this once per machine, and if you will be running a frozen binary (described in Chapter 2) or self-installing system, your setup tasks may be trivial or null.

Is Python Already Present?

Before you do anything else, check whether you already have a recent Python on your machine. If you are working on Linux, Mac OS X, or some Unix systems, Python is probably already installed on your computer, though it may be one or two releases behind the cutting edge. Here’s how to check:

• On Windows 7 and earlier, check whether there is a Python entry in the Start button’s All Programs menu (at the bottom left of the screen). On Windows 8, look for Python in a Start screen tile, your Search tool, the “All apps” display on your Start screen, or a File Explorer ...