How to Install Mono on Debian 10 Buster

Mono platform is used to develop and run cross-platform applications. It is open-source and free implementation by the Microsoft. This tutorial explains how to install Mono on Debian 10.

Prerequisites#

Before you start installation, make sure you have logged in as root or user with sudo privileges.

Installing Mono on Debian#

Standard Debian repositories does not includes Mono package. We will install the Mono package from the official Mono’s repositories. It is a very easy to install. Perform the following steps:

1. Start by installing the necessary packages:

sudo apt update

sudo apt install dirmngr gnupg apt-transport-https ca-certificates

2. Import the repository’s GPG keys using below command:

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

The output should look like below:

gpg: key A6A19B38D3D831EF: public key "Xamarin Public Jenkins (auto-signing) <releng@xamarin.com>" imported
gpg: Total number processed: 1
gpg:               imported: 1

3. Add the Mono repository to your system sources list:

sudo sh -c 'echo "deb https://download.mono-project.com/repo/debian stable-buster main" > /etc/apt/sources.list.d/mono-official-stable.list'

4. Update the packages list and install Mono, after the apt repository is enabled:

sudo apt update

sudo apt install mono-complete

The mono-complete is a meta-package and it will install other required packages for Mono development, including the runtime, development tools, and all libraries.

5. Verify the installation printing the Mono version:

mono --version

At the time of writing this article, the latest stable version of Mono is 6.8.0 Stable (6.8.0.123).

Mono JIT compiler version 6.8.0.123 (tarball Tue Feb  4 21:20:43 UTC 2020)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
    TLS:           __thread
    SIGSEGV:       altstack
    Notifications: epoll
    Architecture:  amd64
    Disabled:      none
    Misc:          softdebug 
    Interpreter:   yes
    LLVM:          yes(610)
    Suspend:       hybrid
    GC:            sgen (concurrent by default)

That’s it. Mono installed successfully on your Debian system, you can start developing your application.

Mono Program Example#

We will create a simple Hello World program to check that everything is set up perfectly.

Open your text editor and create a file named hello.cs with the following content:

using System;

public class HelloWorld
{
    public static void Main(string[] args)
    {
        Console.WriteLine ("Hello World!");
    }
}

To build the program use the csc compiler:

csc hello.cs

It will create a executable with name hello.exe

Run the executable using the command below:

mono hello.exe

The output should show something like this:

Hello, World

Make the file executable to execute the program only by typing its name:

chmod +x hello.exe

You can now run the hello.exe file by typing:

./hello.exe

Conclusion#

You have learned successfully how to install latest stable Mono on Debian from the official Mono repositories.

If you have any question or feedback, please leave a comment below.