@loopback/docs/site/Command-line-interface.md

Documentation files rendered at [https://loopback.io](https://loopback.io)

---
lang: en
title: 'Command-line interface'
keywords: LoopBack 4.0, LoopBack 4, Node.js, TypeScript, OpenAPI, CLI
sidebar: lb4_sidebar
permalink: /doc/en/lb4/Command-line-interface.html
---

LoopBack 4 provides command-line tools to help you get started quickly. The
command line tools generate application and extension projects and install their
dependencies for you. The CLI can also help you generate artifacts, such as
controllers, for your projects. Once generated, the scaffold can be expanded
with users' own code as needed.

To use LoopBack 4's CLI, run this command:

```sh
npm install -g @loopback/cli
```

## Generating LoopBack projects

{% include_relative tables/lb4-project-commands.html %}

## Generating LoopBack artifacts

{% include_relative tables/lb4-artifact-commands.html %}

## Upgrading LoopBack dependencies

When the application is initially scaffolded with `lb4` command, we add the cli
version to `.yo.rc.json`:

```json
{
  "@loopback/cli": {
    "version": "1.21.4"
  }
}
```

To find a compatible list of LoopBack modules for a given version of cli, run:

```sh
lb4 -v
```

It prints out compatible modules that are released with the current version of
cli.

```
@loopback/cli version: 1.23.1

@loopback/* dependencies:
  - @loopback/authentication: ^3.1.1
  - @loopback/boot: ^1.5.8
  - @loopback/build: ^2.0.13
  - @loopback/context: ^1.23.2
  - @loopback/core: ^1.10.4
  - @loopback/metadata: ^1.3.4
  - @loopback/openapi-spec-builder: ^1.2.15
  - @loopback/repository-json-schema: ^1.10.2
  - @loopback/repository: ^1.15.1
  - @loopback/rest: ^1.20.1
  - @loopback/testlab: ^1.9.1
  - @loopback/docs: ^2.2.1
  - @loopback/example-hello-world: ^1.2.16
  - @loopback/example-log-extension: ^1.2.16
  - @loopback/example-rpc-server: ^1.2.16
  - @loopback/example-todo: ^1.8.2
  - @loopback/example-soap-calculator: ^1.6.17
  - @loopback/service-proxy: ^1.3.8
  - @loopback/http-caching-proxy: ^1.1.15
  - @loopback/http-server: ^1.4.15
  - @loopback/example-todo-list: ^1.11.1
  - @loopback/dist-util: ^0.4.0
  - @loopback/rest-explorer: ^1.4.1
  - @loopback/eslint-config: ^4.1.1
  - @loopback/example-express-composition: ^1.7.1
  - @loopback/example-greeter-extension: ^1.3.16
  - @loopback/booter-lb3app: ^1.3.2
  - @loopback/example-lb3-application: ^1.1.16
  - @loopback/example-greeting-app: ^1.2.2
  - @loopback/example-context: ^1.2.16
  - @loopback/repository-tests: ^0.5.1
  - @loopback/health: ^0.2.8
  - @loopback/authorization: ^0.4.1
  - @loopback/rest-crud: ^0.3.2
  - @loopback/security: ^0.1.4
  - @loopback/authentication-passport: ^1.0.1
```

Once a project is generated, running `lb4` commands on the project checks if the
project has incompatible versions with the current cli and prompts users to
proceed or exit.

To update dependencies in the `package.json`, you can use `npm update` or
[npm-check](https://www.npmjs.com/package/npm-check). The existing application
may be broken due to dependency changes. Please make sure build/test/run are
still passing after the upgrade.

## Install shell autocompletion

To enable shell autocompletion with the `tab` key:

```
lb4 install-completion
? Which Shell do you use ? (Use arrow keys)
❯ bash
  zsh
  fish
? Which Shell do you use ? bash
? We will install completion to ~/.bashrc, is it ok ? Yes
=> Tabtab line already exists in ~/.config/tabtab/__tabtab.bash file
=> Tabtab line already exists in ~/.bashrc file
=> Wrote completion script to /Users/<user>/.config/tabtab/lb4.bash file

      => Tabtab source line added to ~/.bashrc for lb4 package.

      Make sure to reload your SHELL.
```

Now you can type `lb4` followed by pressing the `tab` keys twice to be prompted
for auto completion, including commands and options.

```sh
$ lb4
app                example            observer           service
controller         extension          openapi            update
copyright          import-lb3-models  relation
datasource         interceptor        repository
discover           model              rest-crud
```

```sh
$ lb4 controller --
--ask-answered    --force-install   --skip-cache
--config          --format          --skip-install
--controllerType  --help            --yes
```

To uninstall it, run:

```sh
lb4 uninstall-completion
```

## Naming Convention

LoopBack 4 uses different convention for naming classes, variables, and files.

- Class name: `PascalCase`.
- File name: `kebab-case`.
- Variable name: `camelCase`.

Here are some examples:

{% include_relative tables/lb4-class-file-naming-convention.html %}