Python Interactive Interpreter :

When you start up Python, you get a prompt similar to the following:

Python 2.5.1 (r251:54869, Apr 18 2007, 22:08:04) 

[GCC 4.0.1 (Apple Computer, Inc. build 5367)] on darwin.

Type "help", "copyright", "credits" or "license" for more information. >>> 

■Note: The exact appearance of the interpreter and its error messages will depend on which version you are using.

It’s an interactive Python interpreter.

Just try the following :

>>> print "Hello, world!"

When you press the Enter key, the following output appears : Hello, world! >>>