Python has lots of standard (and not standard) modules. You can load one of them using the import keyword. Once loaded, you can use functions from the module or access its objects. For example the sys module has a sys.version and a sys.executable variable.

>>> import sys
>>> sys.version
'2.7.3 (default, Apr 10 2012, 23:24:47) [MSC v.1500 64 bit (AMD64)]'
>>> sys.executable

You can also load specific object directly into your code.

>>> from sys import executable
>>> executable

To quit the interpreter call the exit() function.

>>> exit
Use exit() or Ctrl-Z plus Return to exit

The import binds the word sys to whatever it loaded from the file.