The easiest way to install .NET Core on OSX is a little different than the way currently suggested at the Previous link. I suggest using Homebrew, and Homebrew Cask.

Instructions

If you have not already installed Homebrew, install it.

$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Install dotnet using caskroom. This will also automatically install openssl if it’s not already installed.

$ brew update
$ brew tap caskroom/cask
$ brew cask install dotnet

Note: this will work completely once homebrew-cask#23854 is merged. Until then, follow the part of instructions that link the 1.0.0 versions of openssl to your /usr/local/lib folder.

$ ln -s /usr/local/opt/openssl/lib/libcrypto.1.0.0.dylib /usr/local/lib/
$ ln -s /usr/local/opt/openssl/lib/libssl.1.0.0.dylib /usr/local/lib/

Update 2016-08-18: replaced rpath with linking method (diff)