How to make XCOPY in Visual Studio Post Build Event Command Line support both Linux and Windows?

Question

How to make XCOPY in Visual Studio Post Build Event Command Line support both Linux and Windows? I have a post build event command line in my C# project and can works well on windows, but always failed when build in GitHub CI action, due to GitHub CI is using Linux system. Here is my command line:

set solutionDir=$(SolutionDir)
set splitChar=%solutionDir:~-1%
set fileName=blazor.webassembly.js
set originPath=$(SolutionDir)BuildTools%splitChar%%fileName%
set destinationPath=$(TargetDir)wwwroot%splitChar%_framework%splitChar%%fileName%

echo OriginPath=%originPath%
echo DestinationPath=%destinationPath%
XCOPY %originPath% %destinationPath% /Y

XCOPY command works well on windows, and output:

22>OriginPath=C:\GitRepositories\HackSystem\BuildTools\blazor.webassembly.js
22>DestinationPath=C:\GitRepositories\HackSystem\HackSystem.Web\bin\Debug\net6.0\wwwroot\_framework\blazor.webassembly.js

But when deploy to GitHub CI action, always failed:

/home/runner/work/HackSystem/HackSystem/HackSystem.Web/HackSystem.Web.csproj(51,5): error MSB3073: The command "set solutionDir=/home/runner/work/HackSystem/HackSystem/
/home/runner/work/HackSystem/HackSystem/HackSystem.Web/HackSystem.Web.csproj(51,5): error MSB3073: set splitChar=%solutionDir:~-1%
/home/runner/work/HackSystem/HackSystem/HackSystem.Web/HackSystem.Web.csproj(51,5): error MSB3073: set fileName=blazor.webassembly.js
/home/runner/work/HackSystem/HackSystem/HackSystem.Web/HackSystem.Web.csproj(51,5): error MSB3073: set originPath=/home/runner/work/HackSystem/HackSystem/BuildTools%splitChar%%fileName%
/home/runner/work/HackSystem/HackSystem/HackSystem.Web/HackSystem.Web.csproj(51,5): error MSB3073: set destinationPath=/home/runner/work/HackSystem/HackSystem/HackSystem.Web/bin/Release/net6.0/wwwroot%splitChar%_framework%splitChar%%fileName%
/home/runner/work/HackSystem/HackSystem/HackSystem.Web/HackSystem.Web.csproj(51,5): error MSB3073: 
/home/runner/work/HackSystem/HackSystem/HackSystem.Web/HackSystem.Web.csproj(51,5): error MSB3073: echo OriginPath=%originPath%
/home/runner/work/HackSystem/HackSystem/HackSystem.Web/HackSystem.Web.csproj(51,5): error MSB3073: echo DestinationPath=%destinationPath%
/home/runner/work/HackSystem/HackSystem/HackSystem.Web/HackSystem.Web.csproj(51,5): error MSB3073: XCOPY %originPath% %destinationPath% /Y" exited with code 127.
    1 Warning(s)
    1 Error(s)