# download nginx_signing key
wget http:
# add nginx_singning key to the apt program keyring
sudo apt-get add nginx_signing.key
# view system's code name (ubuntu14.04: trusty)
lsb_release -c
# add nginx source to '/etc/apt/sources.list'
$ echo "deb http://nginx.org/packages/ubuntu/ trusty nginx" >> /etc/apt/sources.list
$ echo "deb-src http://nginx.org/package/ubuntu/ trusty nginx" >> /etc/apt/sources.list
# install nginx
apt-get update
apt-get install nginx