Getting the command line interpreter

Question

My application takes a string command and repeatedly executes it during some process, each time with different environment variables. To support any kind of command, I run cmd /C with the command specified and the system takes care of parsing and running the command. However, I think about making the application compatible with Unix .NET implementations by calling sh -c instead on these systems.

So, I want to determine two things in the most portable way - the proper interpreter that should be executed ( cmd on Windows, sh or possibly user-specified on Unix) and the style of variables which it accepts ( %var% on Windows, $var on Unix).

At the moment, I think about checking the COMSPEC environment variable if it points to a Windows-style command-line interpreter and use that, or look for the SHELL variable and use that. Is there a better managed alternative, or is this sufficient?

Answer 1

我可能在这里误解了一些东西，但是为什么不使用System.Environment.OSVersion.Platform ？

Answer 2

I have settled on checking the SHELL and COMSPEC environment variables to find the correct interpreter and its specification.

static void GetSystemShell(out bool comspec, out string fileName, out string arguments)
{
    fileName = Environment.GetEnvironmentVariable("COMSPEC");
    if(fileName != null)
    {
        comspec = true;
    }else{
        fileName = Environment.GetEnvironmentVariable("SHELL");
        if(fileName != null)
        {
            comspec = false;
        }else{
            fileName = "cmd";
            comspec = true;
        }
    }

    if(comspec)
    {
        arguments = "/C";
    }else{
        arguments = "-c";
    }
}

It prefers a COMSPEC -compatible interpreter if both variables are set. There are also differences between how passing a command to the interpreter works, SHELL expects the command as one (properly escaped) argument, while COMSPEC works best simply by wrapping the command in additional quotes.