stdout

I wan to create a pipe between 3 commands: cat = subprocess.Popen("cat /etc/passwd", stdout=subprocess.PIPE) grep = subprocess.Popen("grep '<usernamr>'", stdin=cat.stdout, stdout=subprocess.PIPE) cut = subprocess.Popen("cut -f 3 -d ':'", stdin=grep.stdout, stdout=subprocess.PIPE) for line in cut.stdout: # process each line here But python documentation says: Use communicate() rather than .stdin.write , .stdout.read or .stderr.read to avoid deadlocks due to any of the other OS pipe buffers filling up and blocking the child process. then how should I use cut.stdout ? Can someone explain

I know this has been answered one in another question, but I simply do not understand how it is done. I am trying to get the output of a command line program (Aria2 downloader) into a HTA script so it can be parsed and the download percentage, file size etc can be obtained and updated into a DIV dynamically. Here is the code I have adjusted and have been trying to use but it just locks up the interface until the command line has finished and THEN displays all the output, instead of displaying it as and when it comes through. Const WshRunning = 0 Const WshFinished = 1 Const WshFailed = 2

If I have a windows console program written with c++, is it possible to retrieve that program's standard output, while the program is running? And if not, what would be the best way to rewrite the program? I know I could output to files and continuously check those files for updates. Is there another way? Is there a better way? There are some interesting articles in Code Project: CommandLineHelper (C#) Redirecting an arbitrary Console's Input/Output (MFC/C++) Universal Console Redirector (MFC/C++) Yes, if you start the program yourself: in CreateProcess , you pass a STARTUPINFO where you can

I am trying to understand the behavior of the three streams - stdout , stdin and stderr . I couldn't get the answer from any textbook, so I came here. I know that these three are stored in file descriptor table with file descriptors 0 (stdin), 1 (stdout) and 2 (stderr). I am also aware that these are not merely file descriptors but I/O streams which can be redirected. Ok, so how about sharing? Consider the three cases: When a fork() is called : The child process and parent process shares file descriptors, but do they have the same stdin, stdout and stderr ? When a thread is created : Threads