Para Ubuntu Server 16.4: (Tomado de la pagina: http://www.mono-project.com/docs/getting-started/install/linux/#debian-ubuntu-and-derivatives)
$ 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
Si queremos instalar el Mod Mono, ejecutamos lo siguiente: (tomado de la pagina: http://www.mono-project.com/docs/getting-started/install/linux/#debian-ubuntu-and-derivatives)
$ 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 update
Una vez agregadas las llaves, se procede a instalar via apt-get
$ sudo apt-get install mono-devel $ sudo apt-get install mono-complete $ sudo apt-get install referenceassemblies-pcl $ sudo apt-get install ca-certificates-mono $ sudo apt-get install mono-xsp4