# 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.

## 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 SIGINT and SIGTERM to the child process. Since shells send SIGINT
to the foreground process group on Ctrl-C, uv will only forward a SIGINT to the child process if it
is seen 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.
