Simplify Python Version Control on Your System with Pyenv

Python is a versatile programming language, but different projects may require different versions. Managing multiple versions of Python can be tricky, especially if you want to switch between them easily. That’s where Pyenv comes in handy! In this blog post, we’ll guide you through installing Pyenv, listing installed Python versions, and changing versions globally or locally for specific projects.

🔗 Step 1.1: Install Pyenv

Pyenv is a simple and effective tool for managing multiple Python versions on your system. To get started, you’ll need to install it. Here’s how:

For macOS and Linux:

Open your terminal and run the following command to install Pyenv via Homebrew:

brew install pyenv

Once Pyenv is installed, you’ll need to add it to your system's shell configuration file (.bashrc, .zshrc, or .bash_profile) so that it initializes automatically every time you open a new terminal session. Add the following lines to your shell configuration file:

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

Then, reload the configuration by running:

source ~/.zshrc
# or if using bash
source ~/.bashrc

🔗 Step 1.2: Verify the Installation

To verify that Pyenv was installed correctly, run:

pyenv --version
# output: pyenv 2.4.11

🔗 Step 2: List Installed Python Versions

Once you have Pyenv installed, you can check which Python versions are already installed on your system. This is useful for knowing which versions are available to set globally or locally.

To list all the installed Python versions, run the following command in your terminal:

pyenv versions
'''
output:
  system
  2.7.18
  3.9.19
* 3.12.5
'''

This will display a list of the installed versions, with the currently active one marked by an asterisk (*).

🔗 Step 3: Set a Global Python Version

If you want to change the default Python version used system-wide, Pyenv makes it simple. To set the global Python version, use the pyenv global command followed by the version you want to activate:

pyenv global <python-version>
# example: pyenv global 3.9.19
# this will set Python 3.9.19 as your default Python version
# across all projects on your machine.

🔗 Step 4: Set a Local Python Version for a Project

Sometimes, different projects require different Python versions. To avoid conflicts, Pyenv allows you to set a local Python version for a specific project or directory. This version will be used only when you’re working within that directory.

Navigate to the directory where your project is located, and run the following command:

pyenv local <python-version>
# for instance, if you need Python 2.7.18 for a particular project,
# you would use:
# pyenv local 2.7.18

# Now, Python 2.7.18 will be automatically activated whenever
# you are inside that directory.

🔗 Wrapping Up

Managing multiple Python versions is essential when working on various projects with different dependencies. By using Pyenv, you can easily install, switch, and manage Python versions without disrupting your global environment.