Step 0 in getting python3 virtualenv going. Just for my reference.

python3-virtualenv-start.sh

#!/bin/bash

# http://www.pythonforbeginners.com/basics/how-to-use-python-virtualenv/
# this gives us python 2.7
#virtualenv env ./env

# start venv like this
mkdir env && cd env
virtualenv -p python3 --no-site-packages env .

# decide if you want to work in activated venv or use full paths for everything
use_venv=0
if [[ ${use_venv} == 1 ]]; then
    vpath=''
    source bin/activate
else
    vpath='bin/'
fi

# now we are in active venv and can install some local packages
${vpath}pip install ipython shortuuid django

# see what packages are installed
${vpath}pip freeze

# export package list to recreate elsewhere
${vpath}pip freeze > requirements.pip
# now somewhere else you can
#mkdir env && cd env
#virtualenv -p python3 --no-site-packages env .
#python3 -m pip install -r requirements.pip
# and now you have an identical python environment

# if using activated venv, devativate before you leave
if [[ ${use_venv} == 1 ]]; then deactivate; fi