e925787da3
<!-- Thank you for contributing to uv! To help us out with reviewing, please consider the following: - Does this pull request include a summary of the change? (See below.) - Does this pull request include a descriptive title? - Does this pull request include references to any relevant issues? --> ## Summary When going through the docs at https://docs.astral.sh/uv/guides/install-python/#automatic-python-downloads, when you try to copy and paste the example on Windows, in either PowerShell or cmd.exe the example won't work. Inverting the quotes fixes it, and still works on other shells (I only tried bash under wsl) ## Test Plan On any windows system, from powershell, running the example yields the following error: ``` > uv run --python 3.12 python -c 'print("hello world")' File "<string>", line 1 print(hello world) ^^^^^^^^^^^ SyntaxError: invalid syntax. Perhaps you forgot a comma? ``` on cmd.exe ``` > uv run --python 3.12 python -c 'print("hello world")' ``` (there is no output) Inverting the quotes on powershell ``` > uv run --python 3.12 python -c "print('hello world')" hello world ``` on cmd.exe ``` > uv run --python 3.12 python -c "print('hello world')" hello world ``` <!-- How was it tested? -->
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Installing Python
If Python is already installed on your system, uv will detect and use it without configuration. However, uv can also install and manage Python versions for you.
!!! tip
uv will [automatically fetch Python versions](#automatic-python-downloads) as needed — you don't need to install Python to get started.
Getting started
To install the latest Python version:
$ uv python install
This will install a uv-managed Python version even if there is already a Python installation on your system. If you've previously installed Python with uv, a new version will not be installed.
!!! note
Python does not publish official distributable binaries. As such, uv uses third-party distributions from the [`python-build-standalone`](https://github.com/indygreg/python-build-standalone) project. The project is partially maintained by the uv maintainers and is used by other prominent Python projects (e.g., [Rye](https://github.com/astral-sh/rye), [Bazel](https://github.com/bazelbuild/rules_python)). See the [Python distributions](../concepts/python-versions.md#managed-python-distributions) documentation for more details.
Once Python is installed, it will be used by uv commands automatically.
!!! important
When Python is installed by uv, it will not be available globally (i.e. via the `python` command).
Support for this feature is planned for a future release. In the meantime, use
[`uv run`](../guides/scripts.md#using-different-python-versions) or
[create and activate a virtual environment](../pip/environments.md) to use `python` directly.
Installing a specific version
To install a specific Python version:
$ uv python install 3.12
To install multiple Python versions:
$ uv python install 3.11 3.12
To install an alternative Python implementation, e.g. PyPy:
$ uv python install pypy@3.10
See the python install documentation
for more details.
Viewing Python installations
To view available and installed Python versions:
$ uv python list
See the python list
documentation for more details.
Automatic Python downloads
Note that Python does not need to be explicitly installed to use uv. By default, uv will automatically download Python versions when they are required. For example, the following would download Python 3.12 if it was not installed:
$ uv run --python 3.12 python -c "print('hello world')"
Even if a specific Python version is not requested, uv will download the latest version on demand. For example, the following will create a new virtual environment and download a managed Python version if Python is not found:
$ uv venv
!!! tip
Automatic Python downloads can be [easily disabled](../concepts/python-versions.md#disabling-automatic-python-downloads) if you want more control over when Python is downloaded.
Using an existing Python installation
uv will use existing Python installations if present on your system. There is no configuration necessary for this behavior: uv will use the system Python if it satisfies the requirements of the command invocation. See the Python discovery documentation for details.
To force uv to use the system Python, provide the --python-preference only-system option. See the
Python version preference
documentation for more details.
Next steps
To learn more about uv python, see the Python version concept
page and the command reference.
Or, read on to learn how to run scripts and invoke Python with uv.