Is there a way to make a console application run using only a single file in .NET Core?

Update 2018: .NET Core 3.0 aims to enable a new scenario: packing the .NET Core runtime and all application dependencies into a single executable.

At the moment, there are no fail-safe methods to create a single executable file. Since there are a lot of type-forwarding dll files involved, even ILMerge and similar tools might not produce correct results (though this might improve, the problem is that those scenarios haven't undergone extensive testing, esp. in production applications)

There are currently two ways to deploy a .NET Core application:

• As a "portable application" / "framework-dependent application", requiring a dotnet executable and installed framework on the target machine. Here, the XYZ.runtimeconfig.json is used to determine the framework version to use and also specifies runtime parameters. This deployment model allows running the same code on various platforms (windows, linux, mac)
• As a "self-contained application": Here the entire runtime is included in the published output and an executable is generated (e.g. yourapp.exe). This output is specific to a platform (set via a runtime identifier) and can only be run on the targeted operating system. However, the produced executable is only a small shim that boots the runtime and loads the app's main dll file. This also allows an XYZ.runtimeconfig.json to set additional runtime properties like garbage collection settings.(think of it as a "new" app.config file)

In the future, the CoreRT runtime – which is still under development at the time of writing – aims to allow creating a single pre-compiled native executable that is specific to a runtime and does not require any other files.

Tested with .NET Core 2.2 on a console app:

1. Reference Microsoft.DotNet.ILCompiler package in your output project. You'll need to add MyGet package repository in Visual Studio settings. *
2. Publish the project via command line, dotnet publish C:\src\App\App.csproj -c release -r win-x64 -o output-win-x64. If there's no "Desktop Development for C++" component installed, do it in Visual Studio Installer, or the command will fail.
3. Go to the output folder (e.g. "C:\src\App\output-win-x64") and grab the native image (.exe file).

On Windows it produced a fully functional 5Mb .exe file (compared to original self-contained publish with folder size at ~60Mb). On macOS the ILComplier though produced output without any error, the app crashed with unhandled expection (on the line with LINQ expression).

*Go to "Tools -> Options -> Package Manager -> Package Sources" and add new source at https://dotnet.myget.org/F/dotnet-core/api/v3/index.json

It is possible in .NET Core 3.0+

The feature is enabled by the usage of the following property in your project file (.csproj):

<PropertyGroup>
    <PublishSingleFile>true</PublishSingleFile>
</PropertyGroup>

There are other options as well, such as packaging the pdb into the bundle, or leaving certain files out.

Documentation can be found here: https://docs.microsoft.com/en-us/dotnet/core/deploying/#publish-self-contained

True it just works:

Combine this technique with the Self Contained Deployment workflow, you can get a true "it just works" experience for your user, they don't even have to install the .NET Core runtime for your app to run.

I am currently deploying applications to my clients as single .exe files.

Read more about that here: https://docs.microsoft.com/en-us/dotnet/core/deploying/#self-contained-deployments-scd