# gatsby-cli

The Gatsby command line interface (CLI) is the main tool you use to initialize, build and develop Gatsby sites.

## How to use gatsby-cli

To use the Gatsby CLI you must either:

- Install it globally with `npm install -g gatsby-cli`, where you execute commands with the syntax `gatsby new`, or
- Run commands directly with [`npx`](https://nodejs.dev/en/learn/the-npx-nodejs-package-runner/), where you execute commands with the syntax `npx gatsby new`

Useful Gatsby CLI commands are also pre-defined in [starters](https://gatsbyjs.com/docs/starters/) as [run scripts](https://gatsbyjs.com/docs/glossary#run-script).

## CLI Commands

All the following documentation is available in the tool by running `gatsby --help`.

Available commands are:

- [new](#new)
- [develop](#develop)
- [build](#build)
- [serve](#serve)
- [clean](#clean)
- [info](#info)
- [repl](#repl)

### `new`

Runs an interactive shell with a prompt that helps you set up a [CMS](https://gatsbyjs.com/docs/glossary#cms), styling system and plugins if you wish.

To create a new site with the prompt, execute:

```shell
gatsby new
```

You can also skip the prompt and clone a starter directly from GitHub. For example, to clone a new [gatsby-starter-blog](https://github.com/gatsbyjs/gatsby-starter-blog), execute:

```shell
gatsby new my-new-blog https://github.com/gatsbyjs/gatsby-starter-blog
```

The first argument (e.g. `my-new-blog`) is the name of your site, and the second argument is the GitHub URL of the starter you want to clone.

> Note: The site name should only consist of letters and numbers. If you specify a `.`, `./` or a `<space>` in the name, `gatsby new` will throw an error.

### `develop`

Compiles and serves a development build of your site that reflects your source code changes in the browser in real time. Should be run from the root of your project.

```shell
gatsby develop
```

Options include:

| Option          | Description                                     |
| --------------- | ----------------------------------------------- |
| `-H`, `--host`  | Set host. Defaults to `localhost`               |
| `-p`, `--port`  | Set port. Defaults to `env.PORT` or `8000`      |
| `-o`, `--open`  | Open the site in your (default) browser for you |
| `-S`, `--https` | Use HTTPS                                       |
| `--inspect`     | Opens a port for debugging                      |

To set up HTTPS, follow the [Local HTTPS guide](https://gatsbyjs.com/docs/local-https/).

To include a URL you can access from other devices on the same network, execute:

```shell
gatsby develop -H 0.0.0.0
```

You will see this output:

```shell
You can now view gatsbyjs.com in the browser.
⠀
  Local:            http://0.0.0.0:8000/
  On Your Network:  http://192.168.0.212:8000/ // highlight-line
```

You can use the "On Your Network" URL to access your site within your network.

### `build`

Compiles your site for production so it can be deployed. Should be run from the root of your project.

```shell
gatsby build
```

Options include:

| Option                       | Description                                                                                                                                                      |
| ---------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `--prefix-paths`             | Build site with link paths prefixed (set `pathPrefix` in your config)                                                                                            |
| `--no-uglify`                | Build site without uglifying JS bundles (for debugging)                                                                                                          |
| `--profile`                  | Build site with react profiling. See [Profiling Site Performance with React Profiler](https://gatsbyjs.com/docs/profiling-site-performance-with-react-profiler/) |
| `--open-tracing-config-file` | Tracer configuration file (OpenTracing compatible). See [Performance Tracing](https://gatsbyjs.com/docs/performance-tracing/)                                    |
| `--graphql-tracing`          | Trace (see above) every graphql resolver, may have performance implications.                                                                                     |
| `--no-color`, `--no-colors`  | Disables colored terminal output                                                                                                                                 |

In addition to these build options, there are some optional [build environment variables](https://gatsbyjs.com/docs/how-to/local-development/environment-variables/#build-variables) for more advanced configurations that can adjust how a build runs. For example, setting `CI=true` as an environment variable will tailor output for [dumb terminals](https://en.wikipedia.org/wiki/Computer_terminal#Dumb_terminals).

### `serve`

Serves the production build of your site for testing prior to deployment. Should be run from the root of your project.

```shell
gatsby serve
```

Options include:

| Option           | Description                                                                                    |
| ---------------- | ---------------------------------------------------------------------------------------------- |
| `-H`, `--host`   | Set host. Defaults to `localhost`                                                              |
| `-p`, `--port`   | Set port. Defaults to `9000`                                                                   |
| `-o`, `--open`   | Open the site in your default browser for you                                                  |
| `--prefix-paths` | Serve site with link paths prefixed (if built with `pathPrefix` in your `gatsby-config` file). |

### `info`

Show helpful environment information which is required in bug reports. Should be run from the root of your project.

```shell
gatsby info
```

Options include:

| Option              | Description                                    |
| ------------------- | ---------------------------------------------- |
| `-C`, `--clipboard` | Copy environment information to your clipboard |

### `clean`

Delete the `.cache` and `public` directories. Should be run from the root of your project.

```shell
gatsby clean
```

This is useful as a last resort when your local project seems to have issues or content does not seem to be refreshing. Issues this may fix commonly include:

- Stale data, e.g. this file/resource/etc. isn't appearing
- GraphQL error, e.g. this GraphQL resource should be present but is not
- Dependency issues, e.g. invalid version, cryptic errors in console, etc.
- Plugin issues, e.g. developing a local plugin and changes don't seem to be taking effect

### `repl`

Open a Node.js REPL (interactive shell) with context of your Gatsby environment. Should be run from the root of your project.

```shell
gatsby repl
```

Gatsby will prompt you to type in commands and explore. When it shows this: `gatsby >`, you can type in one of these commands to see their values in real time:

- `babelrc`
- `components`
- `dataPaths`
- `getNodes()`
- `nodes`
- `pages`
- `schema`
- `siteConfig`
- `staticQueries`

To exit the REPL:

- Press `Ctrl+C` or `Ctrl+D` twice, or
- Type `.exit` and press `Enter`

When combined with the [GraphQL explorer](https://gatsbyjs.com/docs/how-to/querying-data/running-queries-with-graphiql/), these REPL commands could be very helpful for understanding your Gatsby site's data.