pyenv for mac

• Set a requirements.txt to record packages: pip freeze > requirements.txt

• Setup new pyenv environment: pyenv virtualenv {python_version} {env_name}
• Set a local python version: pyenv local {env_name}

• Unset that local version: rm .python-version

• Activate environment: pyenv activate {env_name}

• Deactivate env: pyenv deactivate

• List all pyenv environments: pyenv versions
• List all packages in envs: pip list