pyenv-python312-ubuntu.md

🐧🐍 Pyenv & Python 3.12 on Ubuntu — Setup Guide

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1. Install System Dependencies

sudo apt update
sudo apt install -y 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

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2. Install pyenv

curl https://pyenv.run | bash

If you see WARNING: Can not proceed... Kindly remove the '/home/USER/.pyenv' directory first — pyenv is already installed, skip this step.

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3. Add pyenv to Your Shell (bashrc)

echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init -)"' >> ~/.bashrc
source ~/.bashrc

Verify pyenv is working:

pyenv --version
# pyenv 2.x.x

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4. Install Python 3.12

pyenv install 3.12.0

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5. Set the Python Version

Globally (system-wide):

pyenv global 3.12.0

Locally (for a specific project/folder):

cd ~/Desktop/NeSy/backend
pyenv local 3.12.0

The local version creates a .python-version file in the folder and is automatically activated whenever you enter that directory.

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6. Check Python Versions

Python versions installed on the system:

ls /usr/bin/python*

Python versions installed via pyenv:

pyenv versions

Example output:

  system
* 3.12.0
  3.11.5

The * indicates the currently active version.

Check which Python version is currently in use:

python --version
which python

Check which version is active inside the venv:

# (while venv is activated)
python --version
which python

Quick Reference

Action	Command
List all pyenv versions	pyenv versions
Install a Python version	pyenv install 3.12.0
Set global version	pyenv global 3.12.0
Set local version	pyenv local 3.12.0
Check current version	python --version
Check Python path	which python
Create venv	python -m venv .venv
Activate venv	source .venv/bin/activate
Deactivate venv	deactivate
Verify SSL	python -c "import ssl; print(ssl.OPENSSL_VERSION)"