Step-by-step – Mono Ubuntu 18.04 Installation

Installing

2. 2. Setting Up Mono Repository

   How to Add the Mono Repo for Linux Ubuntu

   Mono Repository Setup

   Mono Ubuntu Apt Repo Setup.

3. 3. Installing Mono

   Finally, to Install Mono for Linux Ubuntu
   Simply play:

   sudo apt install mono-devel

   Authenticate with the User Admin Pass.
   If Got “User is Not in Sudoers file” then see: How to Enable sudo.