os.system() does wait for its process to complete before returning. If you are seeing it not wait, the process you are launching is likely detaching itself to run in the background in which case the subprocess.Popen + wait example Dor gave won’t help. Side note: If all you want is subprocess.Popen + wait use subprocess.call: … Read more
Popen.communicate() is a helper method that does a one-time write of data to stdin and creates threads to pull data from stdout and stderr. It closes stdin when its done writing data and reads stdout and stderr until those pipes close. You can’t do a second communicate because the child has already exited by the … Read more
You sure can append the output of subprocess.Popen to a file, and I make a daily use of it. Here’s how I do it: log = open(‘some file.txt’, ‘a’) # so that data written to it will be appended c = subprocess.Popen([‘dir’, ‘/p’], stdout=log, stderr=log, shell=True) (of course, this is a dummy example, I’m not … Read more
In this specific case for capturing ffmpeg’s status output (which goes to STDERR), this SO question solved it for me: FFMPEG and Pythons subprocess The trick is to add universal_newlines=True to the subprocess.Popen() call, because ffmpeg’s output is in fact unbuffered but comes with newline-characters. cmd = “ffmpeg -i in.mp4 -y out.avi” process = subprocess.Popen(cmd, … Read more
Both wait() (with timeout specified) and poll() return None if the process has not yet finished, and something different if the process has finished (I think an integer, the exit code, hopefully 0). Edit: wait() and poll() have different behaviors: wait (without the timeout argument) will block and wait for the process to complete. wait … Read more
I think creating a new process may be overkill. If you’re on Mac or a Unix-based system, you should be able to use signal.SIGALRM to forcibly time out functions that take too long. This will work on functions that are idling for network or other issues that you absolutely can’t handle by modifying your function. … Read more
Try proc.stdin.write(‘yourPassword\n’) proc.stdin.flush() That should work. What you describe sounds like stdin=None where the child process inherits the stdin of the parent (your Python program).
I solved a similar problem I had by switching to the process directory (I was trying to use inkscape) and it solved my problem import subprocess inkscape_dir=r”C:\Program Files (x86)\Inkscape” assert os.path.isdir(inkscape_dir) os.chdir(inkscape_dir) subprocess.Popen([‘inkscape.exe’,”-f”,fname,”-e”,fname_png]) Maybe switching to the process directory will work for you too.
Reading the docs, both subprocess.call and subprocess.check_output are use-cases of subprocess.Popen. One minor difference is that check_output will raise a Python error if the subprocess returns a non-zero exit status. The greater difference is emphasized in the bit about check_output (my emphasis): The full function signature is largely the same as that of the Popen … Read more
I assume you use pty due to reasons outlined in Q: Why not just use a pipe (popen())? (all other answers so far ignore your “NOTE: I don’t want to print out everything at once”). pty is Linux only as said in the docs: Because pseudo-terminal handling is highly platform dependent, there is code to … Read more