Mastering Flask Web Development - Second Edition

Virtualenv basics

Let's initialize virtualenv for our project, as follows:

$ virtualenv env

The extra env tells virtualenv to store all the packages in a folder named env. Virtualenv requires you to start it before it will sandbox your project. You can do this using the following code:

$ source env/bin/activate
# Your prompt should now look like
(env) $

The source command tells Bash to run the env/bin/activate script in the context of the current directory. Let's reinstall Flask in our new sandbox, as follows:

# you won't need sudo anymore
(env) $ pip install flask
# To return to the global Python
(env) $ deactivate