Dotdeb is a repository of extra packages for Debian. Dotdeb has newer versions of Nginx, PHP, MySQL, Redis and other server software than you’d find in the official Debian repos. The instructions provided on Dotdeb tell you how to install various versions of PHP and MySQL but they don’t tell you how to install only Nginx. Here’s how you can do that.
First you add the “All” dotdeb repo to a file your /etc/apt/sources.list.d:
deb http://packages.dotdeb.org wheezy all
Next you create a preferences file in /etc/apt/preferences.d/ with the following contents:
Package: * Pin: release o=packages.dotdeb.org Pin-Priority: 1 Package: nginx* Pin: release o=packages.dotdeb.org Pin-Priority: 500
What this does is set a low priority for all packages in the Dotdeb repo except for Nginx. Now apt will not install a package from Dotdeb unless that package’s name begins with nginx.
Next, tell apt to update it’s cache of repo info and install nginx:
sudo apt-get update sudo apt-get install nginx
For more about package pinning see the man page for apt_preferences.