Execute Python Scripts

[Cai Gengyang]

So I am going through this article on Python for newbies ---http://askpython.com/execute-python-scripts/ 

Managed to create a file with these contents :

1 #!/usr/bin/env python3
2
3 print('hello world')

and saved it as hello.py

Next step, I wanted to open the 'command line' so I can type 'python hello.py' to execute the scripts.

Where do I find the "command line" ?