Command line program/app + C# class method - c#

When working with a command line program, via a c# class method.
How do you determine if the commandline program was successfully executed and the operation it has performed is ok or has failed?
Also how do you get the screen commandline output into the c# class method?


You can use the Process class to execute a command line command.
The following code captures the standard output to output, and assigns the processes exit code to exitCode.
using (Process p = new Process())
{
p.StartInfo.FileName = exeName;
p.StartInfo.Arguments = args;
p.StartInfo.UseShellExecute = false;
p.StartInfo.RedirectStandardOutput = true;
p.Start();
string output = p.StandardOutput.ReadToEnd();
p.WaitForExit();
int exitCode = p.ExitCode;
}


Something like:
Process mycommand = new Process();
mycommand.StartInfo.FileName = "myexe.exe";
mycommand.StartInfo.Arguments = "param1";
mycommand.StartInfo.UseShellExecute = false;
mycommand.StartInfo.RedirectStandardOutput = true;
mycommand.Start();
Console.WriteLine(mycommand.StandardOutput.ReadToEnd());
mycommand.WaitForExit();
You usually determine an exe's state wether the exit code is 0, but that is arguably down to the writer of the exe


I assume you're using the Process class to call the command line app.
You can find the exit code of the process using Process.ExitCode. You can redirect its standard output by setting ProcessStartInfo.RedirectStandardOutput before starting it, and then either using Process.StandardOutput or the Process.OutputDataReceived event.


Take a look at this questionenter link description here.
The additional information you might need is process.ExitCode to see if it was sucessful. Of course, the Main method of the console app must return an exit code when it is unsuccessful, which many do not.


For this, you use the Process.Start method. You can control how the process runs with the passed in ProcessStartInfo:
var myProcess = Process.Start(new ProcessStartInfo {
FileName = "process.exe",
UseShellExecute = false,
RedirectStandardOutput = true,
CreateNoWindow = true
});
if (!myProcess.WaitForExit(5000)) { // give it 5 seconds to exit
myProcess.Kill();
}
if (myProcess.ExitCode != 0) {
// error!
}
var output = myProcess.StandardOutput.ReadToEnd(); // access output

Related

Is there any cmd callback?

Obviously I can execute something with cmd console using Process.Start();
Is there any way to get output of that process? For example, I could have something like...
Process.Start("sample.bat");
... in my C# winforms application and sample.bat will contain something like:
echo sample loaded
First Question: is there any way to retrieve that sample loaded, after bat execution?
Second question: is there a way to use it without popped up console window?

There is an example of exactly how to do this in the Process documentation:
// Start the child process.
Process p = new Process();
// Redirect the output stream of the child process.
p.StartInfo.UseShellExecute = false;
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.FileName = "Write500Lines.exe";
p.Start();
// Do not wait for the child process to exit before
// reading to the end of its redirected stream.
// p.WaitForExit();
// Read the output stream first and then wait.
string output = p.StandardOutput.ReadToEnd();
p.WaitForExit();

Yes, you can use
Process.Start(ProcessStartInfo)
There are a few ways to hook into I/O including ProcessStartInfo.RedirectStandardOutput available. You can use these overloads to read output from your batch files. You can also hook into the Exited event to know when execution is complete.
Use CreateNoWindow for no window.

Set process.StartInfo.RedirectStandardOutput to true and subscribe to process.OutputDataReceived
using (var process = new Process())
{
process.StartInfo = new ProcessStartInfo("exename");
process.StartInfo.RedirectStandardOutput = true;
process.OutputDataReceived += (s, ev) =>
{
string output = ev.Data;
};
process.Start();
process.BeginOutputReadLine();
process.WaitForExit();
}

Passing arguments one by one one in console exe by c# code

I want to run an exe file by my c# code. The exe file is a console application written in c#.
The console application performs some actions which includes writing content in database and writing some files to directory.
The console application (exe file) expects some inputs from user.
Like it first asks , 'Do you want to reset database ?' y for yes and n for no.
again if user makes a choice then application again asks , 'do you want to reset files ?'
y for yes and n for no.
If user makes some choice the console application starts to get executed.
Now I want to run this exe console application by my c# code. I am trying like this
string strExePath = "exe path";
ProcessStartInfo startInfo = new ProcessStartInfo();
startInfo.CreateNoWindow = false;
startInfo.UseShellExecute = false;
startInfo.FileName = strExePath;
startInfo.WindowStyle = ProcessWindowStyle.Hidden;
using (Process exeProcess = Process.Start(startInfo))
{
exeProcess.WaitForExit();
}
I want to know how can I provide user inputs to the console application by my c# code?
Please help me out in this. Thanks in advance.

You can redirect input and output streams from your exe file.
See redirectstandardoutput
and redirectstandardinput for examples.
For reading:
// Start the child process.
Process p = new Process();
// Redirect the output stream of the child process.
p.StartInfo.UseShellExecute = false;
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.FileName = "Write500Lines.exe";
p.Start();
// Do not wait for the child process to exit before
// reading to the end of its redirected stream.
// p.WaitForExit();
// Read the output stream first and then wait.
string output = p.StandardOutput.ReadToEnd();
p.WaitForExit();
For writing:
...
myProcess.StartInfo.RedirectStandardInput = true;
myProcess.Start();
StreamWriter myStreamWriter = myProcess.StandardInput;
myStreamWriter.WriteLine("y");
...
myStreamWriter.Close();

ProcessStartInfo has a constructor that you can pass arguments to:
public ProcessStartInfo(string fileName, string arguments);
Alternatively, you can set it on it's property:
ProcessStartInfo p = new ProcessStartInfo();
p.Arguments = "some argument";

Here is a sample of how to pass arguments to the *.exe file:
Process p = new Process();
// Redirect the error stream of the child process.
p.StartInfo.UseShellExecute = false;
p.StartInfo.RedirectStandardError = true;
p.StartInfo.FileName = #"\filepath.exe";
p.StartInfo.Arguments = "{insert arguments here}";
p.Start();
error += (p.StandardError.ReadToEnd());
p.WaitForExit();

Proccess info gives an error but a bat file does not

I try to start ilasm from C# using class ProcessInfo
string arguments = string.Format("\"{0}\" /exe /output:\"{1}\" /debug=IMPL", ilFullFileName, exeFileFullName);
ProcessStartInfo processStartInfo = new ProcessStartInfo(CILCompiler, arguments);
processStartInfo.UseShellExecute = false;
processStartInfo.CreateNoWindow = false;
processStartInfo.WorkingDirectory = #"c:\Windows\Microsoft.NET\Framework\v4.0.30319\";
using (Process process = Process.Start(processStartInfo))
{
process.WaitForExit();
}
the arguments are:
"path_to_il.il" /exe /output:"path_to_exe.exe" /debug=IMPL
and then it gives me the error:
The application was unable to start correctly (0xc0000007b). Click Ok to close the application.
The odd part of that is, when I do exactly the same actions manually using bat file
"c:\Windows\Microsoft.NET\Framework\v4.0.30319\ilasm.exe" "path_to_il.il" /exe /output:"path_to_exe.exe" /debug=IMPL
pause
it does work.
What did I miss?

I think you need to set the file name as well:
processStartInfo.FileName = "ilasm.exe";

Proper way to run PsList.exe from my C# app and get its output (Or why my code doesn't work)?

Why this code only shows cmd window and never reaches the end ? I want to get the output from PsList into my C# app.
Execution halts on this line: "int exitCode = proc.ExitCode;"
private static void PsList()
{
ProcessStartInfo start = new ProcessStartInfo();
start.FileName = #"C:\PsList.exe";
start.WindowStyle = ProcessWindowStyle.Hidden;
start.CreateNoWindow = true;
start.UseShellExecute = false;
start.RedirectStandardOutput = true;
using (Process proc = Process.Start(start))
{
proc.WaitForExit(4000);
int exitCode = proc.ExitCode;
string exitMsg = proc.StandardOutput.ReadToEnd();
}
}

You might try rearranging things a bit:
using (Process proc = Process.Start(start))
{
string exitMsg = proc.StandardOutput.ReadToEnd();
proc.WaitForExit(4000);
int exitCode = proc.ExitCode;
}
There are many related questions such as How to get log from Process.Start and ResGen.exe stucks when redirect output

Depending on how exactly the execution halts on the proc.ExitCode line, it may be the process isn't finished by the time the ExitCode property is accessed, and then it will throw a InvalidOperationException.
In that case you could check if the process has already exited with proc.HasExited before trying to access the ExitCode property

C#.Net: Why is my Process.Start() hanging?

I'm trying to run a batch file, as another user, from my web app. For some reason, the batch file hangs! I can see "cmd.exe" running in the task manager, but it just sits there forever, unable to be killed, and the batch file is not running. Here's my code:
SecureString password = new SecureString();
foreach (char c in "mypassword".ToCharArray())
password.AppendChar(c);
ProcessStartInfo psi = new ProcessStartInfo();
psi.WorkingDirectory = #"c:\build";
psi.FileName = Environment.SystemDirectory + #"\cmd.exe";
psi.Arguments = "/q /c build.cmd";
psi.UseShellExecute = false;
psi.UserName = "builder";
psi.Password = password;
Process.Start(psi);
If you didn't guess, this batch file builds my application (a different application than the one that is executing this command).
The Process.Start(psi); line returns immediately, as it should, but the batch file just seems to hang, without executing. Any ideas?
EDIT: See my answer below for the contents of the batch file.
The output.txt never gets created.
I added these lines:
psi.RedirectStandardOutput = true;
Process p = Process.Start(psi);
String outp = p.StandardOutput.ReadLine();
and stepped through them in debug mode. The code hangs on the ReadLine(). I'm stumped!

I believe I've found the answer. It seems that Microsoft, in all their infinite wisdom, has blocked batch files from being executed by IIS in Windows Server 2003. Brenden Tompkins has a work-around here:
http://codebetter.com/blogs/brendan.tompkins/archive/2004/05/13/13484.aspx
That won't work for me, because my batch file uses IF and GOTO, but it would definitely work for simple batch files.

Why not just do all the work in C# instead of using batch files?
I was bored so i wrote this real quick, it's just an outline of how I would do it since I don't know what the command line switches do or the file paths.
using System;
using System.IO;
using System.Text;
using System.Security;
using System.Diagnostics;
namespace asdf
{
class StackoverflowQuestion
{
private const string MSBUILD = #"path\to\msbuild.exe";
private const string BMAIL = #"path\to\bmail.exe";
private const string WORKING_DIR = #"path\to\working_directory";
private string stdout;
private Process p;
public void DoWork()
{
// build project
StartProcess(MSBUILD, "myproject.csproj /t:Build", true);
}
public void StartProcess(string file, string args, bool redirectStdout)
{
SecureString password = new SecureString();
foreach (char c in "mypassword".ToCharArray())
password.AppendChar(c);
ProcessStartInfo psi = new ProcessStartInfo();
p = new Process();
psi.WindowStyle = ProcessWindowStyle.Hidden;
psi.WorkingDirectory = WORKING_DIR;
psi.FileName = file;
psi.UseShellExecute = false;
psi.RedirectStandardOutput = redirectStdout;
psi.UserName = "builder";
psi.Password = password;
p.StartInfo = psi;
p.EnableRaisingEvents = true;
p.Exited += new EventHandler(p_Exited);
p.Start();
if (redirectStdout)
{
stdout = p.StandardOutput.ReadToEnd();
}
}
void p_Exited(object sender, EventArgs e)
{
if (p.ExitCode != 0)
{
// failed
StringBuilder args = new StringBuilder();
args.Append("-s k2smtpout.secureserver.net ");
args.Append("-f build#example.com ");
args.Append("-t josh#example.com ");
args.Append("-a \"Build failed.\" ");
args.AppendFormat("-m {0} -h", stdout);
// send email
StartProcess(BMAIL, args.ToString(), false);
}
}
}
}

Without seeing the build.cmd it's hard to tell what is going on, however, you should build the path using Path.Combine(arg1, arg2); It's the correct way to build a path.
Path.Combine( Environment.SystemDirectory, "cmd.exe" );
I don't remember now but don't you have to set UseShellExecute = true ?

Another possibility to "debug" it is to use standardoutput and then read from it:
psi.RedirectStandardOutput = True;
Process proc = Process.Start(psi);
String whatever = proc.StandardOutput.ReadLine();

In order to "see" what's going on, I'd suggest you transform the process into something more interactive (turn off Echo off) and put some "prints" to see if anything is actually happening. What is in the output.txt file after you run this?
Does the bmail actually executes?
Put some prints after/before to see what's going on.
Also add "#" to the arguments, just in case:
psi.Arguments = #"/q /c build.cmd";
It has to be something very simple :)

My guess would be that the build.cmd is waiting for some sort of user-interaction/reply. If you log the output of the command with the "> logfile.txt" operator at the end, it might help you find the problem.

Here's the contents of build.cmd:
#echo off
set path=C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727;%path%
msbuild myproject.csproj /t:Build > output.txt
IF NOT ERRORLEVEL 1 goto :end
:error
bmail -s k2smtpout.secureserver.net -f build#example.com -t josh#example.com -a "Build failed." -m output.txt -h
:end
del output.txt
As you can see, I'm careful not to output anything. It all goes to a file that gets emailed to me if the build happens to fail. I've actually been running this file as a scheduled task nightly for quite a while now. I'm trying to build a web app that allows me to run it on demand.
Thanks for everyone's help so far! The Path.Combine tip was particularly useful.

I think cmd.exe hangs if the parameters are incorrect.
If the batch executes correctly then I would just shell execute it like this instead.
ProcessStartInfo psi = new ProcessStartInfo();
Process p = new Process();
psi.WindowStyle = ProcessWindowStyle.Hidden;
psi.WorkingDirectory = #"c:\build";
psi.FileName = #"C:\build\build.cmd";
psi.UseShellExecute = true;
psi.UserName = "builder";
psi.Password = password;
p.StartInfo = psi;
p.Start();
Also it could be that cmd.exe just can't find build.cmd so why not give the full path to the file?

What are the endlines of you batch? If the code hangs on ReadLine, then the problem might be that it's unable to read the batch file…

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