Angular CLI

Angular CLI

What it means

The Angular CLI (ng) is the official command-line tool for creating, developing, testing, and building Angular projects. It scaffolds new projects and components with consistent structure, wires up build tooling (via esbuild/Vite in modern Angular versions), and wraps common workflows — dev server, testing, linting — behind simple commands.

Examples

npm install -g @angular/cli    # install the CLI globally

ng new my-app                  # scaffold a new project (prompts for options)
cd my-app
ng serve                       # start the dev server at localhost:4200 with live reload

ng generate component user-profile     # or shorthand: ng g c user-profile
ng generate service auth               # or: ng g s auth

ng build                       # production build, output to dist/
ng test                        # run unit tests
ng lint                        # run the linter

Common mistake

Manually creating component files by hand-copying an existing one — this is error-prone (mismatched selectors, stale imports, forgotten registration) compared to ng generate component, which creates all the right files with correct naming and wiring in one step.

# Error-prone: copy-paste an existing component and edit by hand
cp -r src/app/user-profile src/app/user-settings
# now manually fix: class name, selector, template filename references, tests...

# Reliable: let the CLI generate it correctly the first time
ng generate component user-settings

Quick practice

1. What command creates a brand-new Angular project?

   Answer

   ng new my-app

2. What’s the shorthand for ng generate component?

   Answer

   ng g c — e.g. ng g c user-profile.

3. Why is ng generate generally preferred over manually copying an existing component’s files?

   Answer

   It reliably produces correctly-named, correctly-wired files (class name, selector, imports, test scaffold) in one step, avoiding the small mismatches that creep in from manual copy-paste.