pyenv is an invaluable tool for developers who need to manage multiple Python versions seamlessly. It simplifies the development process by offering various plugins, such as pyenv-virtualenv, which enhances virtual environment management, including support for conda environments.

Note for Windows Users: pyenv does not natively support Windows. Instead, use the pyenv-win fork for Windows compatibility.

Installing pyenv

1. Install Required Python Build Dependencies

Before installing pyenv, ensure you have the necessary build dependencies for your operating system.

Mac OS X:

brew install openssl readline sqlite3 xz zlib

Ubuntu/Debian/Mint:

sudo apt-get update
sudo apt-get install make build-essential libssl-dev zlib1g-dev \
libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm \
libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev

Alpine:

apk add --no-cache git bash build-base libffi-dev openssl-dev bzip2-dev zlib-dev readline-dev sqlite-dev 

2. Install pyenv

The quickest way to install pyenv along with some popular plugins is through the pyenv-installer:

curl https://pyenv.run | bash

After the installation, restart your shell to apply the path changes:

exec $SHELL

3. Update pyenv

To keep pyenv up to date, use:

pyenv update

4. Switch Between Python Versions

To switch between different Python versions:

• pyenv local 3.3.3 - Sets Python 3.3.3 in the current directory.
• pyenv global 2.7.3 - Sets Python 2.7.3 globally across all directories.

5. Manage Virtual Environments and Python Versions

• pyenv virtualenv 3.3.3 virtual-env-name - Creates a virtual environment named virtual-env-name using Python 3.3.3.
• pyenv virtualenvs - Lists all created virtual environments.
• pyenv activate virtual-env-name - Activates the specified virtual environment.
• pyenv deactivate - Deactivates the current virtual environment.

Uninstalling pyenv

If you need to uninstall pyenv, it's straightforward. The pyenv executable is located in $PYENV_ROOT, which defaults to ~/.pyenv. To remove it:

rm -fr ~/.pyenv

Additionally, clean up your .bashrc file by removing the following lines:

export PATH="$HOME/.pyenv/bin:$PATH"
eval "$(pyenv init --path)"
eval "$(pyenv virtualenv-init -)"

Conclusion

In summary, pyenv is an efficient tool for managing multiple Python versions and virtual environments on a single machine. Its simplicity and range of features, including the pyenv-virtualenv plugin, make it an essential tool for Python developers.