Mono is an open-source implementation of .NET libraries and enables cross-platform compatible tools. It is ECMA compatible and provides .NET framework to the Linux environment. Mono is developed by Xamarin and .NET Foundation
Once you download Mono, two commands get your C# code compiled and running.
public class HelloWorld
{
static public void Main ()
{
Console.WriteLine ("Hello Mono World");
}
}
mcs hello-world.cs
Mono hello-world.exe