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
popen gives you a file handle on a process’ stdout, not its stderr. Its first argument is interpreted as a shell command, so you can do redirections in it: FILE *p = popen(“prog 2>&1”, “r”); or, if you don’t want the stdout at all, FILE *p = popen(“prog 2>&1 >/dev/null”, “r”); (Any other file besides … 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
You cannot do that just in standard C++, since iostreams and C I/O are entirely separate and unrelated. You could however write your own iostream that’s backed by a C FILE stream. I believe that GCC comes with one such stream class as a library extension. Alternatively, if all you want is an object-y way … Read more
Under Windows, if you invoke the program using the shell START command you should be able to “release” the parent process and allow it to exit. Try START /? at the DOS prompt to learn more.
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 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. In this case, … Read more
Use Popen.wait: process = subprocess.Popen([“your_cmd”]…) process.wait() Or check_output, check_call which all wait for the return code depending on what you want to do and the version of python. If you are using python >= 2.7 and you don’t care about the output just use check_call. You can also use call but that will not raise … 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
To open in a different console, do (tested on Win7 / Python 3): from subprocess import Popen, CREATE_NEW_CONSOLE Popen(‘cmd’, creationflags=CREATE_NEW_CONSOLE) input(‘Enter to exit from Python script…’) Related How can I spawn new shells to run python scripts from a base python script?