I installed Passenger and Nginx on Ubuntu 12.10 using the following command: passenger-install-nginx-module (following instructions at www.modrails.com/documentation/Users guide Nginx.html). When I ran into problems installing my SSL certificate, I found that command line tools like "Nginx -V" produced the following output: "The program 'nginx' can be found in the following packages..."
Update: I've succeeded in configuring SSL correctly using the instructions at the following link: https://library.linode.com/web-servers/nginx/configuration/ssl
I still need to know how to run Nginx commands from the command line. No problems starting and stopping it using the scripts I installed to /etc/init.d/nginx. The nginx install directory is /opt/nginx.