Determining The Operating System C# .NET Program Is Running Under

Periodically, you will need to determine the operating system your code is running under in order to perform different logic. For example, you want the behaviour to be different depending on whether the code is running under Linux, Windows or OSX.

Your first temptation would be to use the Environment.OSVersion.Platform API and retrieve the PlatformID property like so:

switch (Environment.OSVersion.Platform)
{
    case PlatformID.Win32NT: // Windows NT or later
        Console.WriteLine("Windows NT");
        break;
    case PlatformID.MacOSX:
        Console.WriteLine("OSX");
        break;
    case PlatformID.Unix:
        Console.WriteLine("Unix");
        break;
}

This code has two problems:

1. It will never return OSX, as it considers OSX as Unix
2. There is no PlatformID defined for Linux, and so It also considers Linux as Unix

The correct way is to use the RuntimeInformation.IsOSPlatform API like so:

if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
{
  Console.WriteLine("OSX - {RuntimeInformation.OSDescription}");
}
else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
{
  Console.WriteLine($"Linux - {RuntimeInformation.OSDescription}");
}

else if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
  Console.WriteLine($"Windows - {RuntimeInformation.OSDescription}");
}
else
{
  Console.WriteLine($"Other - {RuntimeInformation.OSDescription}");
}

Running under OSX, it prints the following:

OSX - Unix 14.7.1

Under Linux, it prints the following:

OSX - Linux - Unix 5.15.0.122

Under Windows, it prints the following:

Windows - Microsoft Windows NT 10.0.22631.0

Thus, the code will return the correct value whether running under Windows, OSX or Linux.

Happy hacking!