Php artisan make:auth command is not defined

For Laravel >=6

composer require laravel/ui
php artisan ui vue --auth
php artisan migrate

Reference : Laravel Documentation for authentication

it looks you are not using Laravel 5.2, these are the available make commands in L5.2 and you are missing more than just the make:auth command

    make:auth           Scaffold basic login and registration views and routes
    make:console        Create a new Artisan command
    make:controller     Create a new controller class
    make:entity         Create a new entity.
    make:event          Create a new event class
    make:job            Create a new job class
    make:listener       Create a new event listener class
    make:middleware     Create a new middleware class
    make:migration      Create a new migration file
    make:model          Create a new Eloquent model class
    make:policy         Create a new policy class
    make:presenter      Create a new presenter.
    make:provider       Create a new service provider class
    make:repository     Create a new repository.
    make:request        Create a new form request class
    make:seeder         Create a new seeder class
    make:test           Create a new test class
    make:transformer    Create a new transformer.

Be sure you have this dependency in your composer.json file

    "laravel/framework": "5.2.*",

Then run

    composer update

Update for Laravel 6

Now that Laravel 6 is released you need to install laravel/ui.

composer require laravel/ui --dev
php artisan ui vue --auth

You can change vue with react if you use React in your project (see Using React).

And then you need to perform the migrations and compile the frontend

php artisan migrate
npm install && npm run dev

Source : Laravel Documentation for authentication

Want to get started fast? Install the laravel/ui Composer package and run php artisan ui vue --auth in a fresh Laravel application. After migrating your database, navigate your browser to http://your-app.test/register or any other URL that is assigned to your application. These commands will take care of scaffolding your entire authentication system!

Note: That's only if you want to use scaffolding, you can use the default User model and the Eloquent authentication driver.

In Laravel 6.0 make:auth no longer exists. Read more here

A- Shorthand:

Update Nov 18th: Taylor just released Laravel Installer 2.3.0 added a new "--auth" flag to create a new project with the authentication scaffolding installed!

To update laravel installer read here

It means we can do:

laravel new project --auth

cd project

php artisan migrate

npm install
npm run dev

Which is a shorthand of commands in the Section B. Also read more here

---

B - Details:

Follow these three steps

Step 1 - First do this:

laravel new project

cd project

composer require laravel/ui --dev

Note: Laravel UI Composer package is a new first-party package that extracts the UI portion of a Laravel project ( frontend scaffolding typically provided with previous releases of Laravel ) into a separate laravel/ui package. The separate package enables the Laravel team to update, develop and version UI scaffolding package separately from the primary framework and the main Laravel codebase.

Step 2 - Then do this:

php artisan ui bootstrap --auth
php artisan migrate

or

php artisan ui vue --auth
php artisan migrate

instead of

php artisan make:auth  ( which works for Laravel 5.8 and older versions )

More Options here

php artisan ui:auth

The above command will generate only the auth routes, a HomeController, auth views, and a app.blade.php layout file.

You can also generate the views only with:

php artisan ui:auth --views

The console command will prompt you to confirm overwriting auth files if you've already run the command before.

// Generate basic scaffolding...
php artisan ui vue
php artisan ui react

and also:

// Generate login / registration scaffolding...
php artisan ui vue --auth
php artisan ui react --auth

To see differences read this article

Step 3 - Then you need to do:

npm install
npm run dev