How can I read from standard input and write to standard output. System.Diagnostics.Process.StandardInput's MSDN reference didn't help as it separately starts the process and then redirects the Standard Input/Output but what If the process is already running and called my Application to feed it some data. Here's an example to make things a bit clear:
I am simply using Unix pipes i.e. cat command in cygwin (A Linux like Environment for windows) that basically just reads standard input and print to standard output. following is the command:
% cat input/sample.txt | src/csharp/maptest
But that doesn't seems to work.
If some one know ruby here as i don't here's what i want to do the same in C#:
#!/usr/bin/env ruby
STDIN.each_line
do |line|
some code here
end
And here's some python equivalent code that i want to accomplish in c# or vb.net:
#!/usr/bin/env python
import re
import sys
for line in sys.stdin:
val = line.strip()
Any solutions?
Thanks in advance.
You're looking for the static methods in the Console class :
System.Console.In encapsulate the standard input stream
System.Console.Out encapsulate the standard output stream
Pointers to documentation for System.IO.Pipes are a red herring here.
If you just want the ability to have a process pipe its standard output to another process's standard input, then this works the same as you would expect provided the target process is written to read input from standard input. For example I can do
dir /b /s c:\*.* | findstr exe
to find all executable files on my C: drive.
All you need to do therefore is to build your maptest application so that it reads from standard input, in other words it must accept input via the Console.Read* methods as mentioned in other answers. See this previous question for an earlier discussion
C# Console receive input with pipe
You can't use Console.ReadLine() and Console.WriteLine()?
Never mind the above. Have you tried System.IO.Pipes? Here's the MSDN documentation.
Related
I'm using .NET 6 on Ubuntu 22.04. What is the equivalent C# code to the following Bash code?
echo 'Hello, World!' >&3
Normally, in C# I'd use code like Console.WriteLine("Hello, World!"); to write to stdout. But here, I need to write to file descriptor 3 instead of stdout.
I was able to find some Stack Overflow answers, but they're quite old and deal with Windows APIs which I don't think applies to what I'm trying to do.
I should clarify too that for my use case, redirecting standout output to another file descriptor as I start the .NET process isn't an option. This is is because I need to be able to write to stdout for one purpose, stderr for another, and file descriptor 3 for another. Three purposes in total. This is because the process must be able to be started by a framework that deals with stdout, stderr, and file descriptor 3 these ways. It needs to be compatible.
You should be able to achieve this by writing to /proc/self/fd/3
Use a StreamWriter:
using (StreamWriter outputFile = new StreamWriter("/proc/self/fd/3"))
{
outputFile.WriteLine("Test");
}
Otherwise, you could make a system call to echo, using the command you referenced above, or this...
Process.Start(#"echo Test > /proc/self/fd/3");
I'm starting to work on a chess engine and I want to follow the uci interface where comunication is done using plane text. In the specification it says
all communication is done via standard input and output with text commands
but I dont know what this means in real terms.
I'm thinking of writing in C# as a .net standard library. I understand that as uci is cross platform we cannot talk in language like Console.WriteLine but what does that line in the api mean for me.
Do I have to run a loop listening for Console.ReadLine() or something similar for standard input? I just don't get it. Or should I be writing a console application that takes the input as a command line argument, and writes string to the console?
The full specification can be downloaded from this link:
http://download.shredderchess.com/div/uci.zip
Any process have three default streams:
Standard input (stdin): This is the only input stream for all terminal or console aps. When you cal Console.ReadLine or Console.Read the result is taken from this stream.
Standard Output (stdout): When you call output-related commands in the console singleton class, all data goes here. For example the WriteLine or theWrite methods. The color and beeps commands send data to there too.
Standard error (stderr): This is a dedicated stream to print error-related content to the console. This is dedicated because some applications and scripting solutions want to hide these messages.
You can communicate with the containing process (such a console prompt) with these streams. The command line arguments can be passed only to the program's main method.
I'm trying to redirect that standard output from a Command Line Project I wrote in C# and reading through the data in a Python file.
Currently, the C# application writes data that it reads from a sensor into a CSV file. I have to run the Python file later to get and process the data (has to be done in Python and the data collection has to be done in .NET to use the SDK).
I want to be able to run the C# and the Python projects at the same time and transfer the stream of data directly from the C# to Python project without the use of an intermediate, local file (the CSV).
I've done my own hunting on SO and in the MSDN Documentation. I'm looking at using the ProcessStartInfo.RedirectStandardOutput Property to redirect the console output of the C# application.
I don't yet know how to pick up on the data in this Stream from a Python file. This article was helpful in grasping a better understanding of how to approach it, but I'm still stuck.
I'm also looking at subprocess.Popen.communicate in Python but I'm not yet sure if that would work for what I am asking.
Any help would be appreciated.
Thanks to #Quantic for providing some great resources. Using subprocess.Popen, I can run the built .exe of my C# project and redirect the output to my Python file. I am able now to print() to output to the Python console all the information being output to the C# console (Console.WriteLine()).
Python code:
from subprocess import Popen, PIPE, STDOUT
p = Popen('ConsoleDataImporter.exe', stdout = PIPE, stderr = STDOUT, shell = True)
while True:
line = p.stdout.readline()
print(line)
if not line:
break
This gets the console output of the .NET project line by line as it is created and breaks out of the enclosing while loop upon the project's termination.
I'm wanting to know if it's possible to get the stream that refers to the Powershell console window (in Powershell), assuming one exists. For example, in C# .NET it would be done simply by Console.OpenStandardOutput(). Is there an equivalent in Powershell?
What I'm looking to do is create a System.IO.BinaryWriter to write to it instead of using Write-Host or the like, mostly for experimentation.
I've tried [Console]::OpenStandardOutput(), but that gives me an empty stream, making me think a different one is in use for Powershell.
I'm working with Powershell V5.0:
Major Minor Build Revision
----- ----- ----- --------
5 0 10240 16384
(Note: PowerShell ISE doesn't use the console, so writing to the stream also won't have any effect.)
Trying to read from the standard output stream won't get you anywhere, it's meant for writing stuff to.
Neither will inspecting the length, as the standard output writer will immediately pick up any input and write it to the screen buffer.
Try this in a console-based host (ie. powershell.exe):
$TestBytes = "Test`n".ToCharArray() -as [byte[]]
$OutStream = [console]::OpenStandardOutput()
$OutStream.Write($TestBytes,0,$TestBytes.Length)
You should see that the string Test is written to the screen (along with a trailing newline)
What I am trying to do is see if I can use the MinGW C++ compiler and debugger to compile files using a C# app. I want to be able to read the output and write to the input (input mainly for the debugger) within the C# app whenever I need to.
Reading from output will be much like Visual Studio does in its 'Output' window durring a project build.
I have used System.Diagnostics.Process before but haven't been able to figure out how to interact with the processes.
So, how do I take control of std input/output?
Redirecting standard input
Reading standard output
The following question shows how to capture standard output:
How do I run a Console Application, capture the output and display it in a Literal?
Writing to standard input is similar -- set RedirectStandardInput to true, and use a streamwriter to write to it:
http://msdn.microsoft.com/en-us/library/system.diagnostics.processstartinfo.redirectstandardinput.aspx