Run Unix commands using PuTTY in C#

Question

I am trying to run Unix commands in PuTTY using C#. I have the below code. But the code is not working. I am not able to open PuTTY.

static void Main(string[] args)
{
    Process cmd = new Process();
    cmd.StartInfo.FileName = @"C:\Windows\System32\cmd";
    cmd.StartInfo.UseShellExecute = false;
    cmd.StartInfo.RedirectStandardInput = false;
    cmd.StartInfo.RedirectStandardOutput = true;
    cmd.Start();
    cmd.StartInfo.Arguments = "C:\Users\win7\Desktop\putty.exe -ssh [email protected] 22 -pw mahi";
}

Solution 1

First, in general, you better use native .NET SSH library, like SSH.NET, instead of running external application.

See How to run commands on SSH server in C#?

---

• The putty.exe is a GUI application. It's intended to interactive use, not for automation. There's no point trying to redirect its standard output, as it's not using it.

• For automation, use another tool from PuTTY package, the plink.exe.
  It's a console application, so you can redirect its standard output/input.

• There's no point trying to execute an application indirectly via the cmd.exe. Execute it directly.

• You need to redirect standard input too, to be able to feed commands to the Plink.

• You have to provide arguments before calling the .Start().

• You may want to redirect error output too (the RedirectStandardError). Though note that you will need to read output and error output in parallel, what complicates the code.

---

static void Main(string[] args)
{
    Process cmd = new Process();
    cmd.StartInfo.FileName = @"C:\Program Files (x86)\PuTTY\plink.exe";
    cmd.StartInfo.UseShellExecute = false;
    cmd.StartInfo.RedirectStandardInput = true;
    cmd.StartInfo.RedirectStandardOutput = true;
    cmd.StartInfo.Arguments = "-ssh [email protected] 22 -pw mahi";
    cmd.Start();
    cmd.StandardInput.WriteLine("./myscript.sh");
    cmd.StandardInput.WriteLine("exit");
    string output = cmd.StandardOutput.ReadToEnd();
}

Solution 2

This should work:

    static void Main(string[] args)
    {
        ProcessStartInfo cmd = new ProcessStartInfo();
        cmd.FileName = @"C:\Users\win7\Desktop\putty.exe";
        cmd.UseShellExecute = false;
        cmd.RedirectStandardInput = false;
        cmd.RedirectStandardOutput = true;
        cmd.Arguments = "-ssh [email protected] 22 -pw mahi";
        using (Process process = Process.Start(cmd))
        {
            process.WaitForExit();
        }
    }

Comments

[Martin Prikryl]

While the code indeed executes PuTTY, how does it allow you to execute commands?

[Grady G Cooper]

If you want to run commands, I'd recommend using an SSH library like SSH.NET versus using putty.