> ## Documentation Index
> Fetch the complete documentation index at: https://jncpkg.org/llms.txt
> Use this file to discover all available pages before exploring further.

# jnc install

> Install an environment, updating the lock file if needed.

# jnc install

Installs an environment by resolving dependencies and populating the environment prefix. If the lock file is not up-to-date with the manifest, it will be updated first.

By default, only the `default` environment is installed. Use `--environment` to install a specific environment, or `--all` to install every environment defined in the workspace.

Running `jnc install` is not strictly required before other commands like `jnc run` or `jnc shell` -- those commands automatically install the environment if needed. Use `jnc install` when you want to explicitly prepare an environment ahead of time.

**Alias:** `i`

## Usage

```bash theme={null}
jnc install [OPTIONS]
```

## Options

| Option                       | Description                                                                                  |
| ---------------------------- | -------------------------------------------------------------------------------------------- |
| `-e`, `--environment <ENV>`  | The environment(s) to install. Can be specified multiple times. Defaults to `default`.       |
| `-a`, `--all`                | Install all environments. Conflicts with `--environment`.                                    |
| `--frozen`                   | Use the lockfile as-is, do not update it even if the manifest has changed.                   |
| `--locked`                   | Require the lockfile to be up-to-date with the manifest, abort if not.                       |
| `--skip <PACKAGE>`           | Skip installation of specific packages (soft exclusion -- dependencies are still installed). |
| `--skip-with-deps <PACKAGE>` | Skip a package and its entire dependency subtree (hard exclusion).                           |
| `--only <PACKAGE>`           | Install only these package(s) and their dependencies. Can be specified multiple times.       |

### Global Options

| Option                         | Description                                                       |
| ------------------------------ | ----------------------------------------------------------------- |
| `-m`, `--manifest-path <PATH>` | Path to `jnc.toml`, `pyproject.toml`, or the workspace directory. |

## Examples

### Install the default environment

```bash theme={null}
jnc install
```

### Install a specific environment

```bash theme={null}
jnc install --environment test
```

### Install all environments

```bash theme={null}
jnc install --all
```

### Install using the lock file without updating

```bash theme={null}
jnc install --frozen
```

### Install while skipping a package

```bash theme={null}
jnc install --skip large-package
```

### Install only specific packages and their dependencies

```bash theme={null}
jnc install --only python --only numpy
```