92 lines
2.8 KiB
Markdown
92 lines
2.8 KiB
Markdown
---
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description: The Next.js CLI allows you to start, build, and export your application. Learn more about it here.
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---
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# Next.js CLI
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The Next.js CLI allows you to start, build, and export your application.
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To get a list of the available CLI commands, run the following command inside your project directory:
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```bash
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npx next -h
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```
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_([npx](https://medium.com/@maybekatz/introducing-npx-an-npm-package-runner-55f7d4bd282b) comes with npm 5.2+ and higher)_
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The output should look like this:
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```bash
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Usage
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$ next <command>
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Available commands
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build, start, export, dev, telemetry
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Options
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--version, -v Version number
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--help, -h Displays this message
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For more information run a command with the --help flag
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$ next build --help
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```
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You can pass any [node arguments](https://nodejs.org/api/cli.html#cli_node_options_options) to `next` commands:
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```bash
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NODE_OPTIONS='--throw-deprecation' next
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NODE_OPTIONS='-r esm' next
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NODE_OPTIONS='--inspect' next
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```
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## Build
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`next build` creates an optimized production build of your application. The output displays information about each route.
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- **Size** – The number of assets downloaded when navigating to the page client-side. The size for each route only includes its dependencies.
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- **First Load JS** – The number of assets downloaded when visiting the page from the server. The amount of JS shared by all is shown as a separate metric.
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The first load is colored green, yellow, or red. Aim for green for performant applications.
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You can enable production profiling for React with the `--profile` flag in `next build`. This requires [Next.js 9.5](https://nextjs.org/blog/next-9-5):
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```bash
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next build --profile
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```
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After that, you can use the profiler in the same way as you would in development.
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You can enable more verbose build output with the `--debug` flag in `next build`. This requires Next.js 9.5.3:
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```bash
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next build --debug
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```
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With this flag enabled additional build output like rewrites, redirects, and headers will be shown.
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## Development
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`next dev` starts the application in development mode with hot-code reloading, error reporting, and more:
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The application will start at `http://localhost:3000` by default. The default port can be changed with `-p`, like so:
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```bash
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npx next dev -p 4000
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```
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## Production
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`next start` starts the application in production mode. The application should be compiled with [`next build`](#build) first.
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The application will start at `http://localhost:3000` by default. The default port can be changed with `-p`, like so:
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```bash
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npx next start -p 4000
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```
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## Telemetry
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Next.js collects **completely anonymous** telemetry data about general usage.
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Participation in this anonymous program is optional, and you may opt-out if you'd not like to share any information.
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To learn more about Telemetry, [please read this document](https://nextjs.org/telemetry/).
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