Password protection in NGINX

First, install apache2-utils:

sudo apt install apache2-utils

Generate a password for a specific user:

sudo htpasswd -c /etc/apache2/.htpasswd octomode

Generate another password, for another user (this time without the -c, because that creates a new .htpasswd file):

sudo htpasswd /etc/apache2/.htpasswd user2

Configure nginx:

location /octomode {
    auth_basic "This is a password protected area shared with a peer-to-peer network of trust.";
    auth_basic_user_file /etc/apache2/.htpasswd;
}

From: https://docs.nginx.com/nginx/admin-guide/security-controls/configuring-http-basic-authentication/