Arbitrary scripts with dotnet run

run-cli.csproj

<Project>
  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <OutputType>Exe</OutputType>
    <OutDir>build/bin</OutDir>
    <BaseIntermediateOutputPath>build/obj</BaseIntermediateOutputPath>
  </PropertyGroup>

  <Target Name="PrepareProgram" BeforeTargets="BeforeBuild">
    <PropertyGroup>
      <ProgramPath>$(BaseIntermediateOutputPath)/Program.cs</ProgramPath>
      <ProgramCode><![CDATA[$([MSBuild]::Escape('
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Text.Json;

class Program {
    static int Main(string[] args) {
        var commands = JsonSerializer.Deserialize<Dictionary<string, string>>(File.ReadAllText("run.json"));
        var command = commands[args[0]];

        var process = Process.Start(new ProcessStartInfo("cmd", "/c " + command));
        process.WaitForExit();
        return process.ExitCode;
    }
}
      '))]]></ProgramCode>
    </PropertyGroup>

    <WriteLinesToFile File="$(ProgramPath)" Lines="$(ProgramCode)" Condition="!Exists('$(ProgramPath)')" />
    <ItemGroup>
      <Compile Include="$(ProgramPath)" />
    </ItemGroup>
  </Target>

  <Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk" />

  <ItemGroup>
    <Compile Remove="**/*.*" />
    <None Remove="**/*.*" />
    <Content Remove="**/*.*" />
    <EmbeddedResource Remove="**/*.*" />
  </ItemGroup>

  <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
</Project>

run.json

{
  "custom-command": "echo My custom command"
}

z.console

>dotnet run custom-command
My custom command