A dedicated file extension for file-based app

[skyoxZ]

dotnet [run] app.cs is a great feature that makes it possible to write and run C# code like a script. It would be a benefit if there is a dedicated file extension for such files:

• It helps users to recognize the file is a C# script file to execute.
• The .NET installer could optionally register the file extension with the OS.

[jjonescz]

Given that one of the main motivations of file-based apps is to be compatible with normal C# as much as possible (unlike the previous C# interactive approach which has a different file extension - .csx), I don't think we want to encourage use of other file extensions. Similarly, file-based apps are great starting point for beginners, and it would be confusing if the file extension was different.

That being said, you are free to use other extensions as long as the file has shebang (#!) at the beginning of the file, it will work with dotnet run file. See https://github.com/dotnet/sdk/blob/56e5364b4c3ed9093cb5dec2e6e8dac3544472fa/documentation/general/dotnet-run-file.md#target-path.

cc @dotnet/run-file

[333fred]

Agreed with Jan. I do not think that a dedicated extension is a good thing. Either file.cs or just file, no extension, are the approaches I prefer.