I think I found the answer. By using Popen with close_fds = True I was able to start up a process that was independent and without handles to the parent. For docs look here and search for close_fds. Or, on Windows, if close_fds is true then no handles will be inherited by the child process. … Read more
You obviously can use subprocess.communicate but I think you are looking for real time input and output. readline was blocked because the process is probably waiting on your input. You can read character by character to overcome this like the following: import subprocess import sys process = subprocess.Popen( cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE ) while True: out … Read more
subprocess: The subprocess module allows you to spawn new processes, connect to their input/output/error pipes, and obtain their return codes. http://docs.python.org/library/subprocess.html Usage: import subprocess process = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE) process.wait() print process.returncode
Use the standard subprocess module. You use subprocess.Popen() to start the process, and it will run in the background (i.e. at the same time as your Python program). When you call Popen(), you probably want to set the stdin, stdout and stderr parameters to subprocess.PIPE. Then you can use the stdin, stdout and stderr fields … Read more
Check out the subprocess manual. You have options with subprocess to be able to redirect the stdin, stdout, and stderr of the process you’re calling to your own. from subprocess import Popen, PIPE, STDOUT p = Popen([‘grep’, ‘f’], stdout=PIPE, stdin=PIPE, stderr=STDOUT) grep_stdout = p.communicate(input=”one\ntwo\nthree\nfour\nfive\nsix\n”)[0] print grep_stdout You can also interact with a process line by … Read more
I think you’re looking for something more like the multiprocessing module: http://docs.python.org/library/multiprocessing.html#the-process-class The subprocess module is for spawning processes and doing things with their input/output – not for running functions. Here is a multiprocessing version of your code: from multiprocessing import Process, Queue # must be a global function def my_function(q, x): q.put(x + 100) … Read more
I think you want to instantiate two separate Popen objects here, one for ‘ls’ and the other for ‘sed’. You’ll want to pass the first Popen object’s stdout attribute as the stdin argument to the 2nd Popen object. Example: p1 = subprocess.Popen(‘ls …’, stdout=subprocess.PIPE) p2 = subprocess.Popen(‘sed …’, stdin=p1.stdout, stdout=subprocess.PIPE) print p2.communicate() You can keep … Read more
To get all stdout as a string: from subprocess import check_output as qx cmd = r’C:\Tools\Dvb_pid_3_0.exe’ output = qx(cmd) To get both stdout and stderr as a single string: from subprocess import STDOUT output = qx(cmd, stderr=STDOUT) To get all lines as a list: lines = output.splitlines() To get lines as they are being printed … Read more
You can use a pipe to read the data from the program’s stdout and write it to all the places you want: import sys import subprocess logfile = open(‘logfile’, ‘w’) proc=subprocess.Popen([‘cat’, ‘file’], stdout=subprocess.PIPE, stderr=subprocess.STDOUT) for line in proc.stdout: sys.stdout.write(line) logfile.write(line) proc.wait() UPDATE In python 3, the universal_newlines parameter controls how pipes are used. If False, … Read more
You should pass the arguments as a list (recommended): subprocess.Popen([“wc”, “-l”, “sorted_list.dat”], stdout=subprocess.PIPE) Otherwise, you need to pass shell=True if you want to use the whole “wc -l sorted_list.dat” string as a command (not recommended, can be a security hazard). subprocess.Popen(“wc -l sorted_list.dat”, shell=True, stdout=subprocess.PIPE) Read more about shell=True security issues here.