Add notes about dnx

[baronfel]

Summary

Add a brief snippet about the new dnx script and how it should be packaged by distro maintainers.

Fixes dotnet/sdk#49649

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[baronfel]

@MichaelSimons / @tmds is it reasonable to add the version-independent dnx script to the host package as a recommendation? If adding to an existing package isn't allowed for reasons I'm happy to suggest a new package.

[tmds]

it reasonable to add the version-independent dnx script to the host package as a recommendation?

Yes, this sounds good to me, it's the simplest solution.

[tmds]

@baronfel we also need a symlink similar to (10).

[baronfel]

@baronfel we also need a symlink similar to (10).

of course! That's kind of a critical part of making everything Just Work ™️ . Thanks for the review.

[MichaelSimons]

Attention @dotnet/distro-maintainers

[mateusrodrigues]

If dotnet dnx is an SDK command, should dnx be packaged in the dotnet-host package rather than the dotnet-sdk-X.Y package?

e.g., if the user installs only the runtime (dotnet-runtime-X.Y), which pulls in dotnet-host, they will have a dnx script that doesn't work because there is no SDK, as I understand it.

EDIT: Now that I think about it, I guess the issue is that multiple SDK packages would then provide the same set of files, which is a problem. I'm curious, though, to know how dnx would handle the non-existence of dotnet dnx when there's no SDK installed.

[tmds]

Suggested change

	- **Contains:** (1),(8),(9),(10),(16),(22)
	- **Contains:** (1),(8),(9),(10),(16),(22),(23)

[tmds]

Now that I think about it, I guess the issue is that multiple SDK packages would then provide the same set of files, which is a problem.

Yes, the dotnet-host package contains a bunch of files that shared between different runtime/SDK versions.

I'm curious, though, to know how dnx would handle the non-existence of dotnet dnx when there's no SDK installed.

If there's a runtime installed but no SDK, then you'll get:

The command could not be loaded, possibly because:
  * You intended to execute a .NET application:
      The application 'dnx' does not exist.
  * You intended to execute a .NET SDK command:
      No .NET SDKs were found.

Download a .NET SDK:
https://aka.ms/dotnet/download

Learn about SDK resolution:
https://aka.ms/dotnet/sdk-not-found

And if your SDK doesn't know dnx yet (8.0/9.0):

Could not execute because the specified command or file was not found.
Possible reasons for this include:
  * You misspelled a built-in dotnet command.
  * You intended to execute a .NET program, but dotnet-dnx does not exist.
  * You intended to run a global tool, but a dotnet-prefixed executable with this name could not be found on the PATH.