Develop Reference

how to get Powershell output of this code? [duplicate]

I would like to run an external command line program from my Mono/.NET app.
For example, I would like to run mencoder. Is it possible:
To get the command line shell output, and write it on my text box?
To get the numerical value to show a progress bar with time elapsed?

When you create your Process object set StartInfo appropriately:
var proc = new Process
{
StartInfo = new ProcessStartInfo
{
FileName = "program.exe",
Arguments = "command line arguments to your executable",
UseShellExecute = false,
RedirectStandardOutput = true,
CreateNoWindow = true
}
};
then start the process and read from it:
proc.Start();
while (!proc.StandardOutput.EndOfStream)
{
string line = proc.StandardOutput.ReadLine();
// do something with line
}
You can use int.Parse() or int.TryParse() to convert the strings to numeric values. You may have to do some string manipulation first if there are invalid numeric characters in the strings you read.

You can process your output synchronously or asynchronously.
1. Synchronous example
static void runCommand()
{
Process process = new Process();
process.StartInfo.FileName = "cmd.exe";
process.StartInfo.Arguments = "/c DIR"; // Note the /c command (*)
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
process.Start();
//* Read the output (or the error)
string output = process.StandardOutput.ReadToEnd();
Console.WriteLine(output);
string err = process.StandardError.ReadToEnd();
Console.WriteLine(err);
process.WaitForExit();
}
Note that it's better to process both output and errors: they must be handled separately.
(*) For some commands (here StartInfo.Arguments) you must add the /c directive, otherwise the process freezes in the WaitForExit().
2. Asynchronous example
static void runCommand()
{
//* Create your Process
Process process = new Process();
process.StartInfo.FileName = "cmd.exe";
process.StartInfo.Arguments = "/c DIR";
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
//* Set your output and error (asynchronous) handlers
process.OutputDataReceived += new DataReceivedEventHandler(OutputHandler);
process.ErrorDataReceived += new DataReceivedEventHandler(OutputHandler);
//* Start process and handlers
process.Start();
process.BeginOutputReadLine();
process.BeginErrorReadLine();
process.WaitForExit();
}
static void OutputHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
//* Do your stuff with the output (write to console/log/StringBuilder)
Console.WriteLine(outLine.Data);
}
If you don't need to do complicate operations with the output, you can bypass the OutputHandler method, just adding the handlers directly inline:
//* Set your output and error (asynchronous) handlers
process.OutputDataReceived += (s, e) => Console.WriteLine(e.Data);
process.ErrorDataReceived += (s, e) => Console.WriteLine(e.Data);

Alright, for anyone who wants both Errors and Outputs read, but gets deadlocks with any of the solutions, provided in other answers (like me), here is a solution that I built after reading MSDN explanation for StandardOutput property.
Answer is based on T30's code:
static void runCommand()
{
//* Create your Process
Process process = new Process();
process.StartInfo.FileName = "cmd.exe";
process.StartInfo.Arguments = "/c DIR";
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
//* Set ONLY ONE handler here.
process.ErrorDataReceived += new DataReceivedEventHandler(ErrorOutputHandler);
//* Start process
process.Start();
//* Read one element asynchronously
process.BeginErrorReadLine();
//* Read the other one synchronously
string output = process.StandardOutput.ReadToEnd();
Console.WriteLine(output);
process.WaitForExit();
}
static void ErrorOutputHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
//* Do your stuff with the output (write to console/log/StringBuilder)
Console.WriteLine(outLine.Data);
}

The standard .NET way of doing this is to read from the Process' StandardOutput stream. There is an example in the linked MSDN docs. Similar, you can read from StandardError, and write to StandardInput.

It is possible to get the command line shell output of a process as described here : http://www.c-sharpcorner.com/UploadFile/edwinlima/SystemDiagnosticProcess12052005035444AM/SystemDiagnosticProcess.aspx
This depends on mencoder. If it ouputs this status on the command line then yes :)

you can use shared memory for the 2 processes to communicate through, check out MemoryMappedFile
you'll mainly create a memory mapped file mmf in the parent process using "using" statement then create the second process till it terminates and let it write the result to the mmf using BinaryWriter, then read the result from the mmf using the parent process, you can also pass the mmf name using command line arguments or hard code it.
make sure when using the mapped file in the parent process that you make the child process write the result to the mapped file before the mapped file is released in the parent process
Example:
parent process
private static void Main(string[] args)
{
using (MemoryMappedFile mmf = MemoryMappedFile.CreateNew("memfile", 128))
{
using (MemoryMappedViewStream stream = mmf.CreateViewStream())
{
BinaryWriter writer = new BinaryWriter(stream);
writer.Write(512);
}
Console.WriteLine("Starting the child process");
// Command line args are separated by a space
Process p = Process.Start("ChildProcess.exe", "memfile");
Console.WriteLine("Waiting child to die");
p.WaitForExit();
Console.WriteLine("Child died");
using (MemoryMappedViewStream stream = mmf.CreateViewStream())
{
BinaryReader reader = new BinaryReader(stream);
Console.WriteLine("Result:" + reader.ReadInt32());
}
}
Console.WriteLine("Press any key to continue...");
Console.ReadKey();
}
Child process
private static void Main(string[] args)
{
Console.WriteLine("Child process started");
string mmfName = args[0];
using (MemoryMappedFile mmf = MemoryMappedFile.OpenExisting(mmfName))
{
int readValue;
using (MemoryMappedViewStream stream = mmf.CreateViewStream())
{
BinaryReader reader = new BinaryReader(stream);
Console.WriteLine("child reading: " + (readValue = reader.ReadInt32()));
}
using (MemoryMappedViewStream input = mmf.CreateViewStream())
{
BinaryWriter writer = new BinaryWriter(input);
writer.Write(readValue * 2);
}
}
Console.WriteLine("Press any key to continue...");
Console.ReadKey();
}
to use this sample, you'll need to create a solution with 2 projects inside, then you take the build result of the child process from %childDir%/bin/debug and copy it to %parentDirectory%/bin/debug then run the parent project
childDir and parentDirectory are the folder names of your projects on the pc
good luck :)

You can log process output using below code:
ProcessStartInfo pinfo = new ProcessStartInfo(item);
pinfo.CreateNoWindow = false;
pinfo.UseShellExecute = true;
pinfo.RedirectStandardOutput = true;
pinfo.RedirectStandardInput = true;
pinfo.RedirectStandardError = true;
pinfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
var p = Process.Start(pinfo);
p.WaitForExit();
Process process = Process.Start(new ProcessStartInfo((item + '>' + item + ".txt"))
{
UseShellExecute = false,
RedirectStandardOutput = true
});
process.WaitForExit();
string output = process.StandardOutput.ReadToEnd();
if (process.ExitCode != 0) {
}

How to launch a process (such as a bat file, perl script, console program) and have its standard output displayed on a windows form:
processCaller = new ProcessCaller(this);
//processCaller.FileName = #"..\..\hello.bat";
processCaller.FileName = #"commandline.exe";
processCaller.Arguments = "";
processCaller.StdErrReceived += new DataReceivedHandler(writeStreamInfo);
processCaller.StdOutReceived += new DataReceivedHandler(writeStreamInfo);
processCaller.Completed += new EventHandler(processCompletedOrCanceled);
processCaller.Cancelled += new EventHandler(processCompletedOrCanceled);
// processCaller.Failed += no event handler for this one, yet.
this.richTextBox1.Text = "Started function. Please stand by.." + Environment.NewLine;
// the following function starts a process and returns immediately,
// thus allowing the form to stay responsive.
processCaller.Start();
You can find ProcessCaller on this link: Launching a process and displaying its standard output

I was running into the infamous deadlock problem when calling Process.StandardOutput.ReadLine and Process.StandardOutput.ReadToEnd.
My goal/use case is simple. Start a process and redirect it's output so I can capture that output and log it to the console via .NET Core's ILogger<T> and also append the redirected output to a file log.
Here's my solution using the built in async event handlers Process.OutputDataReceived and Process.ErrorDataReceived.
var p = new Process
{
StartInfo = new ProcessStartInfo(
command.FileName, command.Arguments
)
{
RedirectStandardOutput = true,
RedirectStandardError = true,
UseShellExecute = false,
}
};
// Asynchronously pushes StdOut and StdErr lines to a thread safe FIFO queue
var logQueue = new ConcurrentQueue<string>();
p.OutputDataReceived += (sender, args) => logQueue.Enqueue(args.Data);
p.ErrorDataReceived += (sender, args) => logQueue.Enqueue(args.Data);
// Start the process and begin streaming StdOut/StdErr
p.Start();
p.BeginOutputReadLine();
p.BeginErrorReadLine();
// Loop until the process has exited or the CancellationToken is triggered
do
{
var lines = new List<string>();
while (logQueue.TryDequeue(out var log))
{
lines.Add(log);
_logger.LogInformation(log)
}
File.AppendAllLines(_logFilePath, lines);
// Asynchronously sleep for some time
try
{
Task.Delay(5000, stoppingToken).Wait(stoppingToken);
}
catch(OperationCanceledException) {}
} while (!p.HasExited && !stoppingToken.IsCancellationRequested);

The solution that worked for me in win and linux is the folling
// GET api/values
[HttpGet("cifrado/{xml}")]
public ActionResult<IEnumerable<string>> Cifrado(String xml)
{
String nombreXML = DateTime.Now.ToString("ddMMyyyyhhmmss").ToString();
String archivo = "/app/files/"+nombreXML + ".XML";
String comando = " --armor --recipient bibankingprd#bi.com.gt --encrypt " + archivo;
try{
System.IO.File.WriteAllText(archivo, xml);
//String comando = "C:\\GnuPG\\bin\\gpg.exe --recipient licorera#local.com --armor --encrypt C:\\Users\\Administrador\\Documents\\pruebas\\nuevo.xml ";
ProcessStartInfo startInfo = new ProcessStartInfo() {FileName = "/usr/bin/gpg", Arguments = comando };
Process proc = new Process() { StartInfo = startInfo, };
proc.StartInfo.RedirectStandardOutput = true;
proc.StartInfo.RedirectStandardError = true;
proc.Start();
proc.WaitForExit();
Console.WriteLine(proc.StandardOutput.ReadToEnd());
return new string[] { "Archivo encriptado", archivo + " - "+ comando};
}catch (Exception exception){
return new string[] { archivo, "exception: "+exception.ToString() + " - "+ comando };
}
}

System.Diagnostics.Process is not the most pleasant to work with, so you may want to try CliWrap. It offers many different models for working with output, including piping, buffering, and real-time streaming. Here are some examples (taken from readme).
Simply launch a command line executable:
using CliWrap;
var result = await Cli.Wrap("path/to/exe")
.WithArguments("--foo bar")
.WithWorkingDirectory("work/dir/path")
.ExecuteAsync();
// Result contains:
// -- result.ExitCode (int)
// -- result.StartTime (DateTimeOffset)
// -- result.ExitTime (DateTimeOffset)
// -- result.RunTime (TimeSpan)
Launch a command line executable and buffer stdout/stderr in-memory:
using CliWrap;
using CliWrap.Buffered;
// Calling `ExecuteBufferedAsync()` instead of `ExecuteAsync()`
// implicitly configures pipes that write to in-memory buffers.
var result = await Cli.Wrap("path/to/exe")
.WithArguments("--foo bar")
.WithWorkingDirectory("work/dir/path")
.ExecuteBufferedAsync();
// Result contains:
// -- result.StandardOutput (string)
// -- result.StandardError (string)
// -- result.ExitCode (int)
// -- result.StartTime (DateTimeOffset)
// -- result.ExitTime (DateTimeOffset)
// -- result.RunTime (TimeSpan)
Launch a command line executable with manual pipe configuration:
using CliWrap
var buffer = new StringBuilder();
var result = await Cli.Wrap("foo")
.WithStandardOutputPipe(PipeTarget.ToFile("output.txt"))
.WithStandardErrorPipe(PipeTarget.ToStringBuilder(buffer))
.ExecuteAsync();
Launch a command line executable as an event stream:
using CliWrap;
using CliWrap.EventStream;
var cmd = Cli.Wrap("foo").WithArguments("bar");
await foreach (var cmdEvent in cmd.ListenAsync())
{
switch (cmdEvent)
{
case StartedCommandEvent started:
_output.WriteLine($"Process started; ID: {started.ProcessId}");
break;
case StandardOutputCommandEvent stdOut:
_output.WriteLine($"Out> {stdOut.Text}");
break;
case StandardErrorCommandEvent stdErr:
_output.WriteLine($"Err> {stdErr.Text}");
break;
case ExitedCommandEvent exited:
_output.WriteLine($"Process exited; Code: {exited.ExitCode}");
break;
}
}

Process doesn't appear to be running in C# application

I have this class which runs a process:
public static async Task<ProcessResult> ExecuteShellCommand(string command, string arguments="", int timeout=1000, bool insertWait=false)
{
var result = new ProcessResult();
using (var process = new Process())
{
process.StartInfo.FileName = command;
process.StartInfo.Arguments = arguments;
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardInput = true;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.CreateNoWindow = true;
var outputBuilder = new StringBuilder();
var outputCloseEvent = new TaskCompletionSource<bool>();
process.OutputDataReceived += (s, e) =>
{
// The output stream has been closed i.e. the process has terminated
if (e.Data == null)
{
outputCloseEvent.SetResult(true);
}
else
{
outputBuilder.AppendLine(e.Data);
}
};
var errorBuilder = new StringBuilder();
var errorCloseEvent = new TaskCompletionSource<bool>();
process.ErrorDataReceived += (s, e) =>
{
// The error stream has been closed i.e. the process has terminated
if (e.Data == null)
{
errorCloseEvent.SetResult(true);
}
else
{
errorBuilder.AppendLine(e.Data);
}
};
bool isStarted;
try
{
process.OutputDataReceived += new DataReceivedEventHandler(OutputHandler);
process.ErrorDataReceived += new DataReceivedEventHandler(OutputHandler);
isStarted = process.Start();
StreamReader reader = process.StandardOutput;
string output = reader.ReadToEnd();
result.Output = output;
}
catch (Exception error)
{
// Usually it occurs when an executable file is not found or is not executable
result.Completed = true;
result.ExitCode = -1;
result.Output = error.Message;
isStarted = false;
}
if (isStarted)
{
// Reads the output stream first and then waits because deadlocks are possible
process.BeginOutputReadLine();
process.BeginErrorReadLine();
if (insertWait)
{
await Task.Delay(150000);
}
// Creates task to wait for process exit using timeout
var waitForExit = WaitForExitAsync(process, timeout);
// Create task to wait for process exit and closing all output streams
var processTask = Task.WhenAll(waitForExit, outputCloseEvent.Task, errorCloseEvent.Task);
// Waits process completion and then checks it was not completed by timeout
if (await Task.WhenAny(Task.Delay(timeout), processTask) == processTask && waitForExit.Result)
{
result.Completed = true;
result.ExitCode = process.ExitCode;
// Adds process output if it was completed with error
if (process.ExitCode != 0)
{
result.Output = $"{outputBuilder}{errorBuilder}";
}
}
else
{
try
{
// Kill hung process
process.Kill();
}
catch
{
}
}
}
}
return result;
}
This line calls the ExecuteShellCommand method:
var result = TestHelper.ExecuteShellCommand(MessageInjectorOptions.MessageInjectorFilename, MessageInjectorOptions.MessageInjectorParameters + " " + binaryFile + " " + topic + " " + partition, 300000, true);
My logging shows that this is the command that gets run:
C:\Program Files\Java\jre1.8.0_281\bin\java.exe -jar C:\Users\Administrator\Downloads\test_tool\Jar\Injector\Injector-1.0.jar FILE TOPIC 2
This should push messages contained in FILE to a Kafka topic but the messages don't appear on the topic so I assume the jar doesn't run. If I copy and paste the command to a dos terminal and run it I can see the messages on the topic.
Is there anything wrong with my code that might cause Process to not run correctly?

Connect Process StandardOutput to another Process StandardInput

I'm trying to create a pipeline between several Process objects.
I can run a single Process and capture its StandardOutput, but when I try to connect multiple Process objects, the second one doesn't seem to receive any data from the first one's StandardInput.
In this code, I'm using cat, which either prints the contents of its arguments to stdout, or just copies stdin to stdout.
Using one process works fine:
// Works
private async void launchButtonClicked(object sender, EventArgs e)
{
var outputBuffer = new MemoryStream();
var tasks = new List<Task>();
Process process1;
{
process1 = new Process();
process1.StartInfo.FileName = "cat.exe";
process1.StartInfo.Arguments = "K:\\temp\\streams.txt";
process1.StartInfo.UseShellExecute = false;
process1.StartInfo.RedirectStandardOutput = true;
process1.StartInfo.RedirectStandardInput = false;
process1.StartInfo.CreateNoWindow = true;
process1.EnableRaisingEvents = true;
process1.Start();
}
tasks.Add(process1.StandardOutput.BaseStream.CopyToAsync(outputBuffer));
await Task.WhenAll(tasks);
// OK: This prints the contents of the file
Console.WriteLine("Final output: {0}", UTF8Encoding.UTF8.GetString(outputBuffer.GetBuffer()));
}
But when I add a second process and try to copy Process1's StandardOutput to Process2's StandardInput, I don't ever get any output from Process2 and the await never completes:
// Doesn't work
private async void launchButtonClicked(object sender, EventArgs e)
{
var outputBuffer = new MemoryStream();
var tasks = new List<Task>();
Process process1, process2;
{
process1 = new Process();
process1.StartInfo.FileName = "cat.exe";
process1.StartInfo.Arguments = "K:\\temp\\streams.txt";
process1.StartInfo.UseShellExecute = false;
process1.StartInfo.RedirectStandardOutput = true;
process1.StartInfo.RedirectStandardInput = false;
process1.StartInfo.CreateNoWindow = true;
process1.Start();
}
{
process2 = new Process();
process2.StartInfo.FileName = "cat.exe";
process2.StartInfo.Arguments = "";
process2.StartInfo.UseShellExecute = false;
process2.StartInfo.RedirectStandardOutput = true;
process2.StartInfo.RedirectStandardInput = true;
process2.StartInfo.CreateNoWindow = true;
process2.Start();
}
tasks.Add(process1.StandardOutput.BaseStream.CopyToAsync(process2.StandardInput.BaseStream));
tasks.Add(process2.StandardOutput.BaseStream.CopyToAsync(outputBuffer));
await Task.WhenAll(tasks); // Never returns!
Console.WriteLine("Final output: {0}", UTF8Encoding.UTF8.GetString(outputBuffer.GetBuffer()));
}
Doing something like this works fine from the command line:
C:\>cat.exe K:\temp\streams.txt | cat.exe
... contents of file ...
C:\>
I tried adding Exited event handlers to these Process objects. Process1 exits fine, but Process2 never exits.
I tried some other commands too (like sed), but Process2 still never seems to do anything.
I'm using the streams' BaseStream properties, because I will eventually be working with binary data. (https://stackoverflow.com/a/4535927/339378) This also means I can't use OutputDataReceived, which returns a string (and that would be more complicated anyway).
Thanks!

Apparently, CopyToAsync doesn't close the output stream on completion. This didn't matter for my MemoryStream, but obviously I need to close a process's StandardInput or it won't ever complete.
I made this method:
private static async Task CopyThenClose(Stream from, Stream to)
{
await from.CopyToAsync(to);
to.Close();
}
And replaced the calls to CopyToAsync; eg.:
tasks.Add(CopyThenClose(process1.StandardOutput.BaseStream, process2.StandardInput.BaseStream));

Fail to open file in C# after editing it in another process

I'm using a helper class for running external process:
class ExternalProcessRunner
{
static public string Run(string program, string parameters)
{
output = "";
error = "";
try
{
ProcessStartInfo startInfo = new ProcessStartInfo();
startInfo.CreateNoWindow = true;
startInfo.UseShellExecute = false;
startInfo.FileName = program;
startInfo.Arguments = parameters;
startInfo.WindowStyle = ProcessWindowStyle.Hidden;
startInfo.WindowStyle = ProcessWindowStyle.Minimized;
startInfo.RedirectStandardError = true;
startInfo.RedirectStandardOutput = true;
StringBuilder outputSB = new StringBuilder();
StringBuilder errorSB = new StringBuilder();
using (Process exeProcess = Process.Start(startInfo))
using (AutoResetEvent outputWaitHandle = new AutoResetEvent(false))
using (AutoResetEvent errorWaitHandle = new AutoResetEvent(false))
{
exeProcess.OutputDataReceived += (sender, e) =>
{
if (e.Data == null)
{
outputWaitHandle.Set();
}
else
{
outputSB.AppendLine(e.Data);
}
};
exeProcess.ErrorDataReceived += (sender, e) =>
{
if (e.Data == null)
{
errorWaitHandle.Set();
}
else
{
errorSB.AppendLine(e.Data);
}
};
exeProcess.Start();
exeProcess.BeginOutputReadLine();
exeProcess.BeginErrorReadLine();
exeProcess.WaitForExit();
outputWaitHandle.WaitOne();
errorWaitHandle.WaitOne();
output = outputSB.ToString();
error = errorSB.ToString();
}
}
catch (Exception e)
{
return e.Message;
}
return "";
}
static public string output;
static public string error;
}
It is used to run a perl script which accepts a filename, opens a file, writes some information and closes a file. Then C# code opens that file for reading. Sometimes I get an exception:
"The process cannot access the file 'tmp_file.txt' because it is being used by another process."
What can cause the problem? How to fix it? I think that I'm ensuring the ending of process which means freeing all handles.

Please check you have exited the process i.e. you released the file from the memory.

You can pass in a set number of seconds to wait for the process to exit. Then check if it has exited. If it hasn't, then try and kill the process.
In the example below, it waits for 1 minute for the process to exit. If it doesn't exit, then it sensd a command to close the main window and sleep for 2 seconds. If it still hasn't exited then it tries to kill the process.
At the stage the external process should be gone and the lock released on the file.
exeProcess.WaitForExit(1 * 60 * 1000);
if (!exeProcess.HasExited)
{
_log.Warn("External process has not completed after {0} minutes - trying to close main window", waitTimeMin);
exeProcess.CloseMainWindow();
System.Threading.Thread.Sleep(2000);
}
if (!exeProcess.HasExited)
{
_log.Warn("External process still has not completed - Killing process and waiting for it to exit...");
exeProcess.Kill();
exeProcess.WaitForExit();
}

How can I feed commands to cmd.exe process via an input stream manually?

The question sounds a bit, dense. Here is a slightly longer version:
I need to have the main loop wait for user input and also have a process running and waiting for input from a stream to which the user input is to be sent.
Full story: I'm building a Cmd emulator and at first everything looked fine: The user enters a command, it gets echoed to the output area, processed and StdOut and StdErrOut are captured and also added to the output TextBox.
The only problem was, that, as the cmd process was created and started separately for each command, no state was kept. Neither variables nor codepage nor working directory etc..
So I decided to invent a little hack: Entering an opening or closing parenthesis starts and stops collecting the commands instead of executing them. After the closing parenthesis the list of commands ('batch') is used in the processBatch method to feed them all to the cmd process vie its redirected input. Worked fine.
The only problem was, obviously, now I got state but lost immediate response, so any errors wouldn't pop up until the batch was run.
So I decided to combine the good parts and, well, I knew I was heading for trouble when I realized, that to keep two loops working & waiting I have to use threading. Which I haven't done in years..
In the layout I chose the main() loop waits for user input and startCMDtask() runs startCMD() in a task. Here the input stream is scanned until is has data and then the cmd process is to process them..
But it doesn't work.
List<string> batch = new List<string>();
public volatile string output = "+";
public volatile string outputErr = "-";
Process CMD;
Task cmdTask;
volatile Queue<string> cmdQueue = new Queue<string>();
volatile public bool CMDrunning = false;
Tthis works just fine
private void processBatch()
{
Process p = new Process();
ProcessStartInfo info = new ProcessStartInfo();
info.FileName = "cmd.exe";
info.RedirectStandardOutput = true;
info.RedirectStandardError = true;
info.RedirectStandardInput = true;
info.UseShellExecute = false;
p.StartInfo = info;
p.Start();
using (StreamWriter sw = p.StandardInput)
{
if (sw.BaseStream.CanWrite)
foreach(string line in batch) sw.WriteLine(line);
}
output = "^"; outputErr = "~";
try { output = p.StandardOutput.ReadToEnd(); } catch { }
try { outputErr = p.StandardError.ReadToEnd(); } catch { }
try { p.WaitForExit(); } catch { }
tb_output.AppendText(output + "\r\n" + outputErr + "\r\n");
}
These don't quite, but almost..
private void setupCMD()
{
CMD = new Process();
ProcessStartInfo info = new ProcessStartInfo();
info.FileName = "cmd.exe";
// info.Arguments = "/K"; // doesn't make a difference
info.CreateNoWindow = true;
info.RedirectStandardOutput = true;
info.RedirectStandardError = true;
info.RedirectStandardInput = true;
info.UseShellExecute = false;
CMD.StartInfo = info;
}
private void startCMDtask()
{
var task = Task.Factory.StartNew(() => startCMD());
cmdTask = task;
}
private void startCMD()
{
try { CMD.Start(); CMDrunning = true; }
catch { output = "Error starting cmd process.\r\n"; CMDrunning = false; }
using (StreamWriter sw = CMD.StandardInput)
{
if (sw.BaseStream.CanWrite)
do {
try
{
string cmd = cmdQueue.Dequeue();
if (cmd != null & cmd !="")
{
sw.WriteLine(cmd);
processOutputStreams();
}
}
catch {}
} while (CMDrunning);
}
private void processOutputStreams()
{
string newOutput = ""; string newOutputErr = "";
while (CMD.StandardOutput.Peek() > 0)
newOutput += (char)(CMD.StandardOutput.Read());
newOutput += "!?"; // at this point stdout is correctly captured (1)
try {
while (CMD.StandardError.Peek() > 0) // from here execution jumps away (2)
{ newOutputErr += (char)(CMD.StandardError.Read()); }
} catch {
newOutputErr = "?"; // never comes here
}
lock (output) // no noticable difference
lock (outputErr) //
{ // if I jump here (3) from (1) the result is displayed
// but not if i comment out the 2nd while loop (2)
if (newOutput != null & newOutput != "") output += newOutput + "\r\n";
if (newOutputErr != null & newOutputErr != "") outputErr += newOutputErr + "\r\n";
}
}
This is the call from the input processor in the main thread:
lock (cmdQueue) cmdQueue.Enqueue(cmd);
I have no idea which part is the problem: the process, the cmd shell, the input stream, the output stream, the threading, the locks or all of it in turns..??

I finally got it working. The reason for the erratic behaviour I described in the code samples was that the 3 streams were not accessed in an async'ed manner.
To rectify I discarded the processOutput function and replaced it by two calls that the process itself triggers. MS documetation gives a fine example here
I also made the StreamWriter sync, that feeds the process and the whole task it runs in as well.
Here is the new code:
private void startCMDtask()
{
var task = Task.Factory.StartNew(() => startCMD());
cmdTask = task;
}
private async void startCMD()
{
try { CMD.Start(); CMDrunning = true; }
catch { cmdErrOutput.Append("\r\nError starting cmd process.");
CMDrunning = false; }
CMD.BeginOutputReadLine();
CMD.BeginErrorReadLine();
using (StreamWriter sw = CMD.StandardInput)
{
if (sw.BaseStream.CanWrite)
do {
try
{
string cmd = cmdQueue.Dequeue();
if (cmd != null & cmd !="") await sw.WriteLineAsync(cmd);
}
catch { }
} while (CMDrunning);
try { CMD.WaitForExit(); }
catch { cmdErrOutput.Append("WaitForExit Error.\r\n"); }
}
}
This is how the process is set up now:
private void setupCMD()
{
CMD = new Process();
ProcessStartInfo info = new ProcessStartInfo();
info.FileName = "cmd.exe";
info.CreateNoWindow = true;
info.RedirectStandardOutput = true;
info.RedirectStandardError = true;
info.RedirectStandardInput = true;
info.UseShellExecute = false;
CMD.OutputDataReceived += new DataReceivedEventHandler(cmdOutputDataHandler);
CMD.ErrorDataReceived += new DataReceivedEventHandler(cmdErrorDataHandler);
cmdOutput = new StringBuilder();
cmdErrOutput = new StringBuilder();
CMD.StartInfo = info;
}
And here are the output handlers:
private static void cmdOutputDataHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
if (!String.IsNullOrEmpty(outLine.Data))
{ // Add the text to the collected output.
cmdOutput.Append(Environment.NewLine + outLine.Data);
}
}
private static void cmdErrorDataHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
if (!String.IsNullOrEmpty(outLine.Data))
{ // Add the text to the collected error output.
cmdErrOutput.Append(Environment.NewLine + outLine.Data);
}
}
At the end of the user input porcessing this is how the input queue is ged and the output fetched:
cmdUnDoStack.Push(cmd);
Application.DoEvents();
TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext();
Task.Factory.StartNew(() => updateOutputArea(uiScheduler));
Using this little routine:
private void updateOutputArea(TaskScheduler uiScheduler)
{
Task.Factory.StartNew(() =>
{
tb_output.AppendText(cmdOutput + "\r\n" + cmdErrOutput + "\r\n");
cmdOutput.Clear();
cmdErrOutput.Clear();
}, System.Threading.CancellationToken.None, TaskCreationOptions.None, uiScheduler);
}
And now for the special treament some of the good old commands like CLS or COLOR need.. ;-)