Conventions used in this Book

A line starting with $ in this typeface shown represents the operating system command line prompt:

$ python -V

OS X/Linux troubleshooting: using sudo before commands

A treatise on user file system privileges is outside the scope of this book, but sudo allows you to assume full privileges over the machine you're working on for a given period (after which you'll be asked for a password again). You're first ask for a password, and if it matches the administrator password for your machine the rest of the command will execute.

Try to execute commands without sudo. In other words, when you see this:

$ sudo python web2py.py

Try it without the sudo first:

$ python web2py.py