Managing a Multi-Python System with pyenv

I ran into the need to have multiple versions of Python installed on my machine at one time - different ones for different projects. Thankfully, I’m not the only one with this need!

Enter pyenv

I won’t bore you with the product details, you can go read those yourself (written by more qualified individuals).

Setup ¶

If you’re on Macos, the setup is cake.

$ brew update

# initial installation
$ brew install pyenv

# update existing installation
$ brew upgrade pyenv

But beware! If you also use zsh, you may need to add ~/.pyenv to your $PATH if you want python --version to utilize the Python version specified by pyenv.

$ touch ~/.zsh.after/pyenv.zsh
$ echo '# add .pyenv to PATH' >> ~/.zsh.after/pyenv.zsh
$ echo 'export PATH="/Users/username/.pyenv:$PATH"' >> ~/.zsh.after/pyenv.zsh
$ echo 'eval "$(pyenv init -)"' >> ~/.zsh.after/pyenv.zsh
$ echo '' >> ~/.zsh.after/pyenv.zsh

Note that you’ll need to update username with your system’s username.

Usage ¶

Now you’re golden! Go play with your Python versions!

# view currently installed pyenv versions
$ pyenv versions

# view list of installable Python versions
$ pyenv install --list

# install specific Python version
$ pyenv install 3.7.0

# uninstall specific Python version
$ pyenv uninstall 2.6.9

# set local Python version
$ pyenv local 2.7.15

# unset local Python version
$ pyenv local --unset

# set global Python version
$ pyenv global 3.7.0