When developing several applications on one machine, it becomes useful to separate out dependencies into virtual environments.

With the use of [virtualenv](<https://github.com/pypa/virtualenv/blob/master/README.rst>), these environments are sourced into your shell so that when you run a command, it comes from that virtual environment.

This is most commonly installed using pip.

pip install <https://github.com/pypa/virtualenv/tarball/15.0.2>

Create a new environment

virtualenv --python=python3.5 my_env

Activate the environment

source my_env/bin/activate