# Dive Into Python

Python from novice to pro

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## 1.8. The Interactive Shell

Now that you have Python installed, what's this interactive shell thing you're running?

It's like this: Python leads a double life. It's an interpreter for scripts that you can run from the command line or run like applications, by double-clicking the scripts. But it's also an interactive shell that can evaluate arbitrary statements and expressions. This is extremely useful for debugging, quick hacking, and testing. I even know some people who use the Python interactive shell in lieu of a calculator!

Launch the Python interactive shell in whatever way works on your platform, and let's dive in with the steps shown here:

### Example 1.5. First Steps in the Interactive Shell

    >>> 1 + 1
    2
    >>> print 'hello world'
    hello world
    >>> x = 1
    >>> y = 2
    >>> x + y
    3

| The Python interactive shell can evaluate arbitrary Python expressions, including any basic arithmetic expression.
| The interactive shell can execute arbitrary Python statements, including the print statement.
| You can also assign values to variables, and the values will be remembered as long as the shell is open (but not any longer than that).