A simple and quick approach to use .NET 5 Preview with VS Code on Linux.

Before install, it's important to check .NET 5 - Supported OS versions

Installing

1 - Create a directory to use for the download location and change it into that directory, for example:

mkdir $HOME/dotnet_install && cd $HOME/dotnet_install

2 - Download the shell script with instructions:

curl -H 'Cache-Control: no-cache' -L https://aka.ms/install-dotnet-preview 
-o install-dotnet-preview.sh

3 - Run the script to begin the install:

sudo bash install-dotnet-preview.sh

The last step will download and unzip all packages and dependencies into dotnet_packages/ and then start the installation.

But if the environment is not "clean", it is possible that packages conflicts happen. In this case, the script will stop the execution, then we can do the installations manually, solving or replacing dependencies with conflicts.

cd dotnet_install

ls -l
  dotnet-5.0.0-preview.5-rpm.tar.gz  
  dotnet_packages/  
  install-dotnet-preview.sh

Use a package manager of your preference, and install all the SDKs, Runtimes, and dependencies packages. In this example, we decided to replace files:

cd dotnet_packages

ls -l
  aspnetcore-runtime-5.0.0-preview.5.20279.2-x64.rpm
  aspnetcore-targeting-pack-5.0.0-preview.5.20279.2.rpm
  dotnet-apphost-pack-5.0.0-preview.5.20278.1-x64.rpm
  dotnet-host-5.0.0-preview.5.20278.1-x64.rpm
  dotnet-hostfxr-5.0.0-preview.5.20278.1-x64.rpm
  dotnet-runtime-5.0.0-preview.5.20278.1-x64.rpm
  dotnet-runtime-deps.rpm
  dotnet-sdk-5.0.100-preview.5.20279.10-x64.rpm
  dotnet-targeting-pack-5.0.0-preview.5.20278.1-x64.rpm
  netstandard-targeting-pack-2.1.0-x64.rpm

sudo rpm -i --replacefiles netstandard-targeting-pack-2.1.0-x64.rpm

It's important to maintain the default CLI alias like dotnet because VS Code will use this way to create and run applications.

OR

If you prefer a more simple setup, you can install it using Snap. But, after install, is necessary to change alias from CLI:

sudo snap alias dotnet-sdk.dotnet dotnet

[IMPORTANT] If the dotnet CLI already installed, it's not recommended to use Snap installation, because it's occurrence in an isolated environment and it's not possible to have double alias like dotnet.

For more instructions or ways to install SDK/Runtime, use this documentation.

VS Code settings

To enjoy new features from C# 9 is necessary to install or update VS Code for version 1.46.

Some recommended extensions: C# and C# Extensions.

Projects settings

Now, we can build applications using preview version from .NET 5 just indicating on C Sharp Project (*.CSPROJ) file the respective versions from framework and language:

<Project Sdk="Microsoft.NET.Sdk.Web">

    <PropertyGroup>
        <TargetFramework>net5.0</TargetFramework>
        <LangVersion>preview</LangVersion>
    </PropertyGroup>

</Project>

Enjoy!