Microsoft open sourcing the .NET Core Runtime. This will include everything needed to execute .NET code – including the CLR, Just-In-Time Compiler (JIT), Garbage Collector (GC), and core .NET base class libraries under the MIT open source license.
This process will allow the .NET teams in Microsoft to collaborate even more deeply with other developers around the world. The result is going to be even better products for everyone.
You can download full source code from below link:https://github.com/dotnet/corefx
Fore more details, visit below linkshttp://weblogs.asp.net/scottgu/announcing-open-source-of-net-core-framework-net-core-distribution-for-linux-osx-and-free-visual-studio-community-edition