Required package

• For Debian: apache2-utils.

  sudo apt-get install apache2-utils

• For Fedora: httpd-tools.

  sudo dnf install httpd-tools

Create password file

Run with -c option if /etc/nginx/.htpasswd does not exist:

sudo htpasswd -c /etc/nginx/.htpasswd user1

If .htpasswd already exists, don't use -c option or file will be overwritten.
To add more user to password file.

sudo htpasswd /etc/nginx/.htpasswd user2