/home/cli2/test
   /bin/Debug/netcoreapp2.1/subdir/
      a.out
   /obj
   Program.cs
   test.csproj

process.StartInfo.FileName = "a.out"
process.StartInfo.UseShellExecute = false;
process.StartInfo.WorkingDirectory = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location) + "/subdir/";

Unhandled Exception: System.ComponentModel.Win32Exception: No such file or directory

/home/cli2/project
   /bin/Debug/netcoreapp2.1/subdir/
   /obj
   Program.cs
   test.csproj
   a.out