e61a221fef
## Summary We want to have consistency between the Ruff and uv documentation for the upcoming release. We don't love the Ruff docs, but we'd rather have consistency and then work towards improving them both, rather than have two very-different documentation sites that both have weaknesses. The setup here is simpler than in Ruff as: (1) we don't yet generate any docs from Rust and (2) we don't try to reuse the README in the uv documentation (which adds a lot of complexity in Ruff). So the change here is mostly a 1-to-1 port to MkDocs. ## Test Plan 
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Installing Python
uv can manage Python installations — Python does not need to be installed to use uv.
To install Python:
$ uv python install
This will install a uv-managed Python version even if there is already a Python installation on the system.
Once Python is installed, it can be invoked via python:
$ python --version
To prevent uv from managing Python system-wide, provide the --no-shim option during installation.
Installing a specific version
To install a specific Python version:
$ uv python install 3.12
See the Python versions 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 one hasn't been installed yet:
$ uv venv --python-preference only-managed
Note that when an automatic Python installation occurs, the python command will not be added to the shell. Use uv python install-shim to ensure the python shim is installed.
Using an existing Python installation
uv will also use an existing Python installation if already present on the system. There's no configuration necessary for this behavior, uv will use the system Python if it satisfies the requirements of the command invocation.
To force uv to use the system Python, provide the --python-preference only-system option.
See the Python version preference documentation for more details.