In an interactive Python session, you type some Python code after the prompt, >>>. The Python interpreter reads and executes what you type, carrying out your various commands.

To start an interactive session, run the Python 3 application. Type python3 at a terminal prompt (Mac/Unix/Linux) or open the Python 3 application in Windows.

If you see the Python prompt, >>>, then you have successfully started an interactive session. These notes depict example interactions using the prompt, followed by some input.

>>> 2 + 2
4

Interactive controls. Each session keeps a history of what you have typed. To access that history, press <Control>-P (previous) and <Control>-N (next). <Control>-D exits a session, which discards this history. Up and down arrows also cycle through history on some systems.