> ## 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 lock

> Solve the environment and update the lock file without installing.

# jnc lock

Solves all environments defined in the workspace manifest and writes an updated `jnc.lock` file. Unlike `jnc install`, this command does not install any packages into an environment prefix -- it only computes and persists the dependency resolution.

This is useful in CI workflows, validation checks, or when you want to preview what would change before installing.

## Usage

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

## Options

| Option         | Description                                                                                            |
| -------------- | ------------------------------------------------------------------------------------------------------ |
| `--json`       | Output the changes to the lock file in JSON format.                                                    |
| `--check`      | Check if the lock file would change. Exits with a non-zero code if changes are detected. Useful in CI. |
| `--dry-run`    | Compute the lock file without writing to disk. Implies `--no-install`.                                 |
| `--no-install` | Do not install the environment (default behavior for `lock`, but can be made explicit).                |

### Global Options

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

## Examples

### Update the lock file

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

### Check if the lock file is up-to-date (CI use)

```bash theme={null}
jnc lock --check
```

### Preview lock file changes without writing

```bash theme={null}
jnc lock --dry-run
```

### Output lock file changes as JSON

```bash theme={null}
jnc lock --json
```