How to run Roslyn instead csc.exe from command line?

Roslyn from command line('cmd'), Windows 10 scenario example:
( Note: No need Visual Studio installed, but only the .NET core )

1. Open 'cmd' and create folder "dotnet-csharp-tools":

   D:>mkdir "dotnet-csharp-tools"

2. Navigate to folder "dotnet-csharp-tools":

   D:>cd "dotnet-csharp-tools"

3. In folder "dotnet-csharp-tools" download 'nuget.exe' latest version from:

   https://www.nuget.org/downloads

4. Check name of the last version of 'Microsoft.CodeDom.Providers.DotNetCompilerPlatform' from:

   https://www.nuget.org/packages/Microsoft.CodeDom.Providers.DotNetCompilerPlatform/

   For example: 'Microsoft.CodeDom.Providers.DotNetCompilerPlatform -Version 3.6.0'

5. From 'cmd'(opened folder "dotnet-csharp-tools"), run command:

   D:\dotnet-csharp-tools>nuget install Microsoft.CodeDom.Providers.DotNetCompilerPlatform -Version 3.6.0

6. From 'cmd' navigate to 'D:\dotnet-csharp-tools\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.3.6.0\tools\Roslyn472'(warning : folder name 'Roslyn472' may be different, if is other version)

   D:\dotnet-csharp-tools>cd Microsoft.CodeDom.Providers.DotNetCompilerPlatform.3.6.0\tools\Roslyn472

7. From 'File explorer' find 'csc.exe'(in the current folder 'Roslyn472'). Make copy of 'csc.exe' with name 'csc-roslyn.exe'(name can be whatever).

8. For 'Windows 10', open:

   'Edit system environment variables' -> 'System variables' -> 'path' -> 'Edit' -> 'New' -> D:\dotnet-csharp-tools\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.3.6.0\tools\Roslyn472

9. Close and open again 'cmd'(the command prompt). This 'cmd' restart needed, because 'system environment variables' are edited.

10. Check if 'csc-roslyn' is recognized by 'cmd' by run command:

    csc-roslyn

11. Create folder 'D:\csharp-projects'(folder name can be whatever) and create in 'D:\csharp-projects' C# source files, for example:

Vehicle.cs

class Vehicle { private string name = "unknown"; private int producedYear = -1; public Vehicle(string name, int producedYear) { this.Name = name; this.ProducedYear = producedYear; } public string Name { get { return this.name; } set { this.name = value; } } public int ProducedYear { get { return this.producedYear; } set { this.producedYear = value; } } } 

Car.cs

class Car : Vehicle { private string maker = "unknown"; public Car(string name, int age, string maker) : base(name, age) { this.Maker = maker; } public string Maker { get { return this.maker; } set { this.maker = value; } } public override string ToString() { return $"{this.Name}, {this.ProducedYear}, {this.Maker}"; } } 

Autoservice.cs

using System; class Autoservice { public static void Main() { Car car1 = new Car("Ford Taunus", 1971, "Ford"); Car car2 = new Car("Opel Ascona", 1978, "Opel"); Car car3 = new Car("Saab 900", 1984, "Saab"); Console.WriteLine(car1); Console.WriteLine(car2); Console.WriteLine(car3); } } 

12. Open 'D:\csharp-projects' from 'cmd'(the command prompt) and run command:

    csc-roslyn /target:exe /out:Autoservice.exe Vehicle.cs Car.cs Autoservice.cs

13. Run from 'cmd':

    Autoservice.exe

14. Result should be:

Ford Taunus, 1971, Ford
Opel Ascona, 1978, Opel
Saab 900, 1984, Saab

I suspect the location of the Roslyn compiler moves around a lot based on the Visual Studio you're running.

I was able to find mine by performing a search like this:

cd "\Program Files (x86)"

dir /s csc*.* | findstr Roslyn

My particular csc.exe was located in:

C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\MSBuild\Current\Bin\Roslyn\csc.exe

The easiest way to invoke csc from the .NET SDK you have installed is via the csc dotnet tool:

dotnet tool install -g csc 

...you can then verify if it has been installed correctly:

asc@ascpixi:~$ csc -version 4.8.0-7.24225.6 (de75b3c7) 

This tool is but a simple wrapper over the managed csc.dll .NET itself uses.

Each .NET SDK installation contains a copy of csc under <SDK location>/Roslyn/bincore/csc.dll - it's a managed assembly you're supposed to execute with e.g. dotnet exec. For example:

asc@ascpixi:~$ dotnet --list-sdks 8.0.107 [/usr/lib/dotnet/sdk] asc@ascpixi:~$ dotnet exec /usr/lib/dotnet/sdk/8.0.107/Roslyn/bincore/csc.dll -version 4.8.0-7.24225.6 (de75b3c7)