angular-docs-cn/aio/content/cli/index.md

CLI Overview and Command Reference

The Angular CLI is a command-line interface tool that you use to initialize, develop, scaffold, and maintain Angular applications directly from a command shell.

Installing Angular CLI

Major versions of Angular CLI follow the supported major version of Angular, but minor versions can be released separately.

Install the CLI using the npm package manager: npm install -g @angular/cli

For details about changes between versions, and information about updating from previous releases, see the Releases tab on GitHub: https://github.com/angular/angular-cli/releases

Basic workflow

Invoke the tool on the command line through the ng executable. Online help is available on the command line. Enter the following to list commands or options for a given command (such as generate) with a short description.

ng help ng generate --help

To create, build, and serve a new, basic Angular project on a development server, go to the parent directory of your new workspace use the following commands:

ng new my-first-project cd my-first-project ng serve

In your browser, open http://localhost:4200/ to see the new app run. When you use the ng serve command to build an app and serve it locally, the server automatically rebuilds the app and reloads the page when you change any of the source files.

When you run ng new my-first-project a new folder, named my-first-project, will be created in the current working directory. Since you want to be able to create files inside that folder, make sure you have sufficient rights in the current working directory before running the command.

If the current working directory is not the right place for your project, you can change to a more appropriate directory by running cd <path-to-other-directory> first.

Workspaces and project files

The ng new command creates an Angular workspace folder and generates a new app skeleton. A workspace can contain multiple apps and libraries. The initial app created by the ng new command is at the top level of the workspace. When you generate an additional app or library in a workspace, it goes into a projects/ subfolder.

A newly generated app contains the source files for a root module, with a root component and template. Each app has a src folder that contains the logic, data, and assets.

You can edit the generated files directly, or add to and modify them using CLI commands. Use the ng generate command to add new files for additional components and services, and code for new pipes, directives, and so on. Commands such as add and generate, which create or operate on apps and libraries, must be executed from within a workspace or project folder.

• See more about the Workspace file structure.

Workspace and project configuration

A single workspace configuration file, angular.json, is created at the top level of the workspace. This is where you can set per-project defaults for CLI command options, and specify configurations to use when the CLI builds a project for different targets.

The ng config command lets you set and retrieve configuration values from the command line, or you can edit the angular.json file directly. Note that option names in the configuration file must use camelCase, while option names supplied to commands can use either camelCase or dash-case.

• See more about Workspace Configuration.
• See the complete schema for angular.json.

CLI command-language syntax

Command syntax is shown as follows:

ng commandNameOrAlias requiredArg [optionalArg] [options]

• Most commands, and some options, have aliases. Aliases are shown in the syntax statement for each command.

• Option names are prefixed with a double dash (--). Option aliases are prefixed with a single dash (-). Arguments are not prefixed. For example: ng build my-app -c production

• Typically, the name of a generated artifact can be given as an argument to the command or specified with the --name option.

• Argument and option names can be given in either camelCase or dash-case. --myOptionName is equivalent to --my-option-name.

Boolean and enumerated options

Boolean options have two forms: --thisOption sets the flag, --noThisOption clears it. If neither option is supplied, the flag remains in its default state, as listed in the reference documentation.

Allowed values are given with each enumerated option description, with the default value in bold.

Relative paths

Options that specify files can be given as absolute paths, or as paths relative to the current working directory, which is generally either the workspace or project root.

Schematics

The ng generate and ng add commands take as an argument the artifact or library to be generated or added to the current project. In addition to any general options, each artifact or library defines its own options in a schematic. Schematic options are supplied to the command in the same format as immediate command options.