c# - Redirect but also display process output stream

Question

I am running a build, and I would like to be able to view the progress as it happens. But I would also like to save the output if the build has an error.

I know I can use Process.UseShellExecute = false, and RedirectStandardOutput, but that's only part of the story.

How can I do this?

Answer 1

Maybe like this?

class Tee
{
    private readonly string m_programPath;
    private readonly string m_logPath;
    private TextWriter m_writer;

    public Tee(string programPath, string logPath)
    {
        m_programPath = programPath;
        m_logPath = logPath;
    }

    public void Run()
    {
        using (m_writer = new StreamWriter(m_logPath))
        {

            var process =
                new Process
                {
                    StartInfo =
                        new ProcessStartInfo(m_programPath)
                        { RedirectStandardOutput = true, UseShellExecute = false }
                };

            process.OutputDataReceived += OutputDataReceived;

            process.Start();
            process.BeginOutputReadLine();
            process.WaitForExit();
        }
    }

    private void OutputDataReceived(object sender, DataReceivedEventArgs e)
    {
        Console.WriteLine(e.Data);
        m_writer.WriteLine(e.Data);
    }
}