virtualenv

Create isolated Python environments

TLDR

Create a virtual environment

$ virtualenv [venv]

Create with specific Python

$ virtualenv -p [python3.11] [venv]

Create without pip

$ virtualenv --no-pip [venv]

Create with system packages

$ virtualenv --system-site-packages [venv]

Activate the environment (bash/zsh)

$ source [venv]/bin/activate

Activate the environment (fish)

$ source [venv]/bin/activate.fish

Deactivate the environment

$ deactivate

Create with latest seed packages

$ virtualenv --download [venv]

virtualenv creates isolated Python environments. Each environment has its own Python binary and independent set of installed packages, allowing different projects to have different dependencies without conflicts.When activated, the virtual environment modifies PATH to use the environment's Python and pip, isolating package installations from the system Python. This is essential for reproducible development environments.virtualenv is the original virtual environment tool for Python, predating the built-in venv module. It offers additional features like choosing Python versions and faster environment creation.

PARAMETERS

-p python, --python= python

Python interpreter to use.

--system-site-packages

Give access to system site-packages.

--no-pip

Don't install pip.

--no-setuptools

Don't install setuptools.

--no-wheel

Don't install wheel.

--download

Download latest pip/setuptools/wheel.

--no-download

Use bundled pip/setuptools/wheel.

--clear

Clear existing environment.

--copies

Use copies instead of symlinks.

--prompt text

Custom prompt prefix for the activated environment.

--activators list

Activators to generate (comma-separated: bash, fish, cshell, powershell, etc.).

-v, --verbose

Increase verbosity.

-q, --quiet

Decrease verbosity.

INSTALL

sudo apk add py3-virtualenv

brew install virtualenv

nix profile install nixpkgs#virtualenv

CAVEATS

Environment must be activated in each new shell. Absolute paths are embedded in the environment, making it non-relocatable. Python version must exist on system. Consider using python -m venv for basic needs.

HISTORY

virtualenv was created by Ian Bicking in 2007 to address Python's lack of built-in environment isolation. It became the standard tool for Python development before venv was added to the standard library in Python 3.3. virtualenv remains popular due to additional features and Python 2 support (historical).