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Using Python on Linux & Unix Platforms

Virtually every Linux distribution relies heavily on Python for operating system maintenance, package management tools (like apt, dnf, and yum), and system services. This guide covers distribution packages, PEP 668 restrictions, and building Python from source.

Distribution Package Managers

Different Linux distributions split Python into modular packages:

sudo apt update
# Note: Ubuntu splits virtual environment support into a separate package!
sudo apt install python3 python3-pip python3-venv python3-dev

sudo dnf install python3 python3-pip python3-devel

sudo pacman -S python python-pip

PEP 668: The "Externally Managed Environment" Error

On modern Linux distributions (Debian 12+, Ubuntu 23.04+, Fedora 38+), running pip install <package> globally outputs an error:

error: externally-managed-environment × This environment is externally managed ╰─> To install Python packages system-wide, try 'apt install python3-xyz', where xyz is the package you are trying to install. If you wish to install a non-Debian-packaged Python application, it may be easiest to use pipx.

Why Does This Happen?

In the past, users running sudo pip install would overwrite system Python libraries maintained by apt or dnf, breaking system utilities. PEP 668 prevents this collision.

The Correct Solutions

  1. For Projects: Always use a project virtual environment: 
    python3 -m venv .venv
source .venv/bin/activate
pip install requests
  2. For Global CLI Tools (like Black, Ruff, or MkDocs): Use pipx to install tools into isolated per-application environments: 
    sudo apt install pipx
pipx ensurepath
pipx install mkdocs-material

Compiling Python from Source

When you need the latest Python release before your distribution packages it, or need a debug build, compile from source:

1. Install Build Dependencies

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

sudo dnf groupinstall "Development Tools"
sudo dnf install openssl-devel bzip2-devel libffi-devel \
zlib-devel readline-devel sqlite-devel

2. Configure and Compile

# Download and unpack release tarball
wget https://www.python.org/ftp/python/3.13.0/Python-3.13.0.tgz
tar -xf Python-3.13.0.tgz
cd Python-3.13.0

# Configure with production optimizations
./configure --enable-optimizations --with-lto

# Compile using all available CPU cores
make -j $(nproc)

3. Install with altinstall

Always Use make altinstall, Never make install!

Running sudo make install overwrites the system /usr/bin/python3 binary, breaking your Linux operating system!

sudo make altinstall installs the binary as /usr/local/bin/python3.13 without replacing the system python3 alias:

sudo make altinstall

Verify the installation:

python3.13 --version

Shebang Conventions & Executable Permissions

To make a Python script directly executable from the Linux terminal:

  1. Add the portable shebang line as the first line of the file: 
    #!/usr/bin/env python3
import sys
print(f"Executed via: {sys.executable}")
  2. Grant execute permissions with chmod: 
    chmod +x script.py
  3. Run the script directly: 
    ./script.py