install Mono on ubuntu

install Mono on ubuntu
ref:
http://www.mono-project.com/docs/getting-started/install/linux/#debian-ubuntu-and-derivatives
http://alvin1016.blogspot.tw/2015/03/ubuntunetmono.html
========================================================================

sudo apt-get install mono-complete

sudo apt-get install mono-runtime


# sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF

# echo "deb http://download.mono-project.com/repo/debian wheezy main" | sudo tee /etc/apt/sources.list.d/mono-xamarin.list

# sudo apt-get update

get Error :
GPG error: http://hyperrate.com eliu Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5C577D59835AB0E3

# sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 5C577D59835AB0E3

try again
# sudo apt-get update

# echo "deb http://download.mono-project.com/repo/debian wheezy-apache24-compat main" | sudo tee -a /etc/apt/sources.list.d/mono-xamarin.list

# sudo apt-get install mono-devel  mono-complete referenceassemblies-pcl

=======================================================================

testing mono (hello.cs)

using System;

public class HelloWorld
{
    static public void Main ()
    {
        Console.WriteLine (" Mono Mono ");
    }
}

compile
# mcs hello.cs

Run hello.exe
# mono hello.exe

YO~~~~~~~ it's working ~~~~~