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Installing and Managing Minor Python Versions with Pyenv

pythonpyenvversion-managementminor-version

As a Data Platform Engineer I have to work with different versions of Python all the time. Sometimes I need to pin minor version of Python so all the libraries and functionalities can work together without issue. Also sometime I would like to try out new capabilities and test new functionalities like 3.13t no-gil version.

Prerequisites

I've already installed pyenv using Homebrew and resolved the common installation issues. If you haven't set up pyenv yet or encountered errors, check out my pyenv troubleshooting guide. Also you can check their official documentation for installation instructions on each platform.

My setup:

  • OS: Ubuntu 24.04.3 LTS
  • Pyenv version: 2.6.17

Finding Available Python Versions

You can find all the available versions with this command. I don't even know most of them. To be honest I used minor versioning like 3.11.11 or experiment version like 3.13t. List all available Python versions:

pyenv install --list

This will return huge list of versions.

Installing a Specific Python Version

For example we can install 3.12.7 with this command:

pyenv install 3.12.7

or we can install no-gil version with 3.13t:

pyenv install 3.13t

When you ran the command it will show something like this

Downloading Python-3.12.7.tar.xz...
-> https://www.python.org/ftp/python/3.12.7/Python-3.12.7.tar.xz
Installing Python-3.12.7...

and when finished it will show version and where it installed like this:

Installed Python-3.12.7 to /home/user/.pyenv/versions/3.12.7

Checking Installed Versions

We can list all the available versions in our system with:

pyenv versions

It will show something like this:

* system (set by /home/user/.pyenv/version)
  3.12.7
  3.13.11
  3.13.11t

In here * show us which one is active.

Setting Python Versions

There are 3 option to use in pyenv. We can switch between global, local or shell.

If we change the version on shell it will be active on just the shell session. If we change it for local it means it will be changed for directory. Lastly global change for every global usage of python defaultly.

Personally I never used global version for long time. I never recommend it, if you don't know what are you doing. Always use virtual environments. Change the version in shell or directory create a virtual environment and use that for your project.

Change your directory to your projects directory.

cd ~/projects/my-project

Change your pyenv default version for directory ( Here you can also use shell command but shell command needs extra setup for shells so for simplicity we can use local instead for projects)

pyenv local 3.12.7

When you run this command it will create a .python-version file in the directory and it just save the version name there. If you check current version with:

pyenv versions

You should see the location of the asterisk (*) changed. Now it is next to version you selected.

Now we can check python version:

python --version

This should return the version we specified. If not or giving error like

Command 'python' not found, did you mean:
  command 'python3' from deb python3
  command 'python' from deb python-is-python3

This means shell integration is not set up. In their documentation there is a section on setting up your shell environment to integrate with pyenv.

If you don't feel comfortable with this changes you can just run:

eval "$(pyenv init -)"

And from same shell you check again:

python --version

This should return your specified version.

Conclusion

Pyenv is nice tool to be able install minor versions for python. It can be challenging to deal with bash settings but it can be used without it too. Just don't forget to activate your virtual environments when you are installing additional dependencies to your Python environment.

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