How to configure a basic authentication with Nginx on Ubuntu?

bash

echo -n 'admin:' >> /etc/nginx/.htpasswd
openssl passwd -apr1 >> /etc/nginx/.htpasswd
cat /etc/nginx/.htpasswd
vim /etc/nginx/sites-available/default
service nginx reload

/etc/nginx/sites-available/default

auth_basic "Restricted Content";
auth_basic_user_file /etc/nginx/.htpasswd;