If you want to write the output to a file you can use the stdout-argument of subprocess.call. It takes either None (the default, stdout is inherited from the parent (your script)) subprocess.PIPE (allows you to pipe from one command/process to another) a file object or a file descriptor (what you want, to have the output … Read more
subprocess.Popen takes a list of arguments: from subprocess import Popen, PIPE process = Popen([‘swfdump’, ‘/tmp/filename.swf’, ‘-d’], stdout=PIPE, stderr=PIPE) stdout, stderr = process.communicate() There’s even a section of the documentation devoted to helping users migrate from os.popen to subprocess.
What your code tries to do is call a program named cd … What you want is call a command named cd. But cd is a shell internal. So you can only call it as subprocess.call(‘cd ..’, shell=True) # pointless code! See text below. But it is pointless to do so. As no process can … Read more
subprocess.Popen does exactly what you want. from subprocess import Popen p = Popen([‘watch’, ‘ls’]) # something long running # … do other stuff while subprocess is running p.terminate() (Edit to complete the answer from comments) The Popen instance can do various other things like you can poll() it to see if it is still running, … Read more
Here is how to suppress output, in order of decreasing levels of cleanliness. They assume you are on Python 3. You can redirect to the special subprocess.DEVNULL target. import subprocess subprocess.run([‘ls’, ‘-l’], stdout=subprocess.DEVNULL) # The above only redirects stdout… # this will also redirect stderr to /dev/null as well subprocess.run([‘ls’, ‘-l’], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL) # Alternatively, … Read more
I tried this, and for some reason while the code for line in p.stdout: … buffers aggressively, the variant while True: line = p.stdout.readline() if not line: break … does not. Apparently this is a known bug: http://bugs.python.org/issue3907 (The issue is now “Closed” as of Aug 29, 2018)
Use shell=True if you’re passing a string to subprocess.call. From docs: If passing a single string, either shell must be True or else the string must simply name the program to be executed without specifying any arguments. subprocess.call(crop, shell=True) or: import shlex subprocess.call(shlex.split(crop))
If you check out the subprocess section of the Python docs, you’ll notice there is an example of how to replace os.system() with subprocess.Popen(): sts = os.system(“mycmd” + ” myarg”) …does the same thing as… sts = Popen(“mycmd” + ” myarg”, shell=True).wait() The “improved” code looks more complicated, but it’s better because once you know … Read more
There are two ways to do the redirect. Both apply to either subprocess.Popen or subprocess.call. Set the keyword argument shell = True or executable = /path/to/the/shell and specify the command just as you have it there. Since you’re just redirecting the output to a file, set the keyword argument stdout = an_open_writeable_file_object where the object … Read more
subprocess.Popen takes a cwd argument to set the Current Working Directory; you’ll also want to escape your backslashes (‘d:\\test\\local’), or use r’d:\test\local’ so that the backslashes aren’t interpreted as escape sequences by Python. The way you have it written, the \t part will be translated to a tab. So, your new line should look like: … Read more