Question: I'm having a issue trying to write input to linux process. Here the code goes:

```
        System.Diagnostics.Process process = new System.Diagnostics.Process();
        process.StartInfo.WorkingDirectory = "'/home/"+user+"/pacotes/"+nome_pacote.Text+"-1.0/'";
        process.StartInfo.FileName="dh_make";
        process.StartInfo.Arguments="-n -s";
        process.StartInfo.UseShellExecute = false;
        process.StartInfo.RedirectStandardInput = true;
        process.Start();
        Thread.Sleep(3000);
        process.StandardInput.WriteLine();

```

And here goes the error:

> 
> System.IO.IOException: Write fault on path /home/vinholi/Ubuntu One/Uso do linux em flash drives/Programa gerador de .deb/GeradorDeb/GeradorDeb/bin/Debug/[Unknown]
>  at System.IO.FileStream.FlushBuffer (System.IO.Stream st) [0x00000] in :0
>  at System.IO.FileStream.FlushBuffer () [0x00000] in :0
>  at System.IO.FileStream.Dispose (Boolean disposing) [0x00000] in :0
> 
> 
>

Answer: 
One likely explanation for this error is that the process exited before you're attempting to write to it. I tried this with `/bin/date` and a legitimate `StartInfo.WorkingDirectory` and the assembly is `/Workspace/export/misc/H.exe`. This yields:

```
Unhandled Exception:
System.IO.IOException: Write fault on path /Workspace/export/misc/[Unknown]
  at System.IO.FileStream.WriteInternal (System.Byte[] src, Int32 offset, Int32 count) [0x00097] in /Workspace/mono/mcs/class/corlib/System.IO/FileStream.cs:658 
  at System.IO.FileStream.Write (System.Byte[] array, Int32 offset, Int32 count) [0x000aa] in /Workspace/mono/mcs/class/corlib/System.IO/FileStream.cs:634 
  at System.IO.StreamWriter.FlushBytes () [0x00043] in /Workspace/mono/mcs/class/corlib/System.IO/StreamWriter.cs:222 
  at System.IO.StreamWriter.FlushCore () [0x00012] in /Workspace/mono/mcs/class/corlib/System.IO/StreamWriter.cs:203 
  at System.IO.StreamWriter.Write (System.Char[] buffer) [0x00022] in /Workspace/mono/mcs/class/corlib/System.IO/StreamWriter.cs:351 
  at System.IO.TextWriter.WriteLine () [0x00000] in /Workspace/mono/mcs/class/corlib/System.IO/TextWriter.cs:257 
  at X.Main () [0x00066] in /Workspace/export/misc/H.cs:17 

```

You are getting this every time when you're using an invalid directory in `process.StartInfo.WorkingDirectory`. There's nothing that can be done about that, though the error message should be made clearer.

Your directory is invalid because of the quotation marks. You also should not concatenate path names the way you did as it makes your application non-portable to non-Unix operating systems. Instead, write it as:

```
var home = Environment.GetFolderPath (Environment.SpecialFolder.UserProfile);
process.StartInfo.WorkingDirectory = Path.Combine (home, "pacotes", nome_pacote.Text+"-1.0");

```

Using `Environment.GetFolderPath()` makes it easier to run your application on a Mac (where home directories are in `/Users/<username>` instead of `/home/<username>`).
As another response stated "One likely explanation for this error is that the process exited before you're attempting to write to it."

And that was the problem I had -- even after setting the WorkingDirectory as described in the other answer. And in your same situation: C#, Mono, Ubuntu.

Ultimately the solution in my case was to set the Arguments so that the process was not exiting, and was really trying to read input from the StandardInput.