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uv/docs/concepts/projects/run.md
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Brian Dentino ce7808d0cb Update docs to reflect new signal forwarding semantics (#16430)
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## Summary

<!-- What's the purpose of the change? What does it do, and why? -->
I am a new uv user and I was reading the docs to better understand the
project scope & best practices. The section on [signal
forwarding](https://docs.astral.sh/uv/concepts/projects/run/#signal-handling)
with `uv run` caught my eye because I've used tools that use SIGHUP to
trigger config reloads or SIGUSR1/2 to enable debugging/profiling/etc so
I was a little concerned about using a runner that might block those
signals. After some searching in issues/PRs, I found that this behavior
was actually [changed earlier this
year](https://github.com/astral-sh/uv/pull/13017) to forward additional
signals (awesome!) and thought I would update the docs and save the next
person/llm from thinking their tool won't work as expected if it uses
custom signal handling.

Thanks for all your great work!

P.S. If you think it makes more sense to explicitly list all forwarded
signals as opposed to just the exclusions, I'm happy to edit.
2025-10-24 14:52:08 -05:00

101 lines
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Markdown

# Running commands in projects
When working on a project, it is installed into the virtual environment at `.venv`. This environment
is isolated from the current shell by default, so invocations that require the project, e.g.,
`python -c "import example"`, will fail. Instead, use `uv run` to run commands in the project
environment:
```console
$ uv run python -c "import example"
```
When using `run`, uv will ensure that the project environment is up-to-date before running the given
command.
The given command can be provided by the project environment or exist outside of it, e.g.:
```console
$ # Presuming the project provides `example-cli`
$ uv run example-cli foo
$ # Running a `bash` script that requires the project to be available
$ uv run bash scripts/foo.sh
```
## Requesting additional dependencies
Additional dependencies or different versions of dependencies can be requested per invocation.
The `--with` option is used to include a dependency for the invocation, e.g., to request a different
version of `httpx`:
```console
$ uv run --with httpx==0.26.0 python -c "import httpx; print(httpx.__version__)"
0.26.0
$ uv run --with httpx==0.25.0 python -c "import httpx; print(httpx.__version__)"
0.25.0
```
The requested version will be respected regardless of the project's requirements. For example, even
if the project requires `httpx==0.24.0`, the output above would be the same.
## Running scripts
Scripts that declare inline metadata are automatically executed in environments isolated from the
project. See the [scripts guide](../../guides/scripts.md#declaring-script-dependencies) for more
details.
For example, given a script:
```python title="example.py"
# /// script
# dependencies = [
# "httpx",
# ]
# ///
import httpx
resp = httpx.get("https://peps.python.org/api/peps.json")
data = resp.json()
print([(k, v["title"]) for k, v in data.items()][:10])
```
The invocation `uv run example.py` would run _isolated_ from the project with only the given
dependencies listed.
## Legacy scripts on Windows
Support is provided for
[legacy setuptools scripts](https://packaging.python.org/en/latest/guides/distributing-packages-using-setuptools/#scripts).
These types of scripts are additional files installed by setuptools in `.venv\Scripts`.
Currently only legacy scripts with the `.ps1`, `.cmd`, and `.bat` extensions are supported.
For example, below is an example running a Command Prompt script.
```console
$ uv run --with nuitka==2.6.7 -- nuitka.cmd --version
```
In addition, you don't need to specify the extension. `uv` will automatically look for files ending
in `.ps1`, `.cmd`, and `.bat` in that order of execution on your behalf.
```console
$ uv run --with nuitka==2.6.7 -- nuitka --version
```
## Signal handling
uv does not cede control of the process to the spawned command in order to provide better error
messages on failure. Consequently, uv is responsible for forwarding some signals to the child
process the requested command runs in.
On Unix systems, uv will forward most signals (with the exception of SIGKILL, SIGCHLD, SIGIO, and
SIGPOLL) to the child process. Since terminals send SIGINT to the foreground process group on
Ctrl-C, uv will only forward a SIGINT to the child process if it is sent more than once or the child
process group differs from uv's.
On Windows, these concepts do not apply and uv ignores Ctrl-C events, deferring handling to the
child process so it can exit cleanly.