Question

I have a shell script that I want to call from a python program, but doesn’t work at all with following code(Popen already imported):

bf_dir = '/home/wireless'
bf_path = os.path.join(bf_dir, 'airdispatch.sh')
sh = Popen("sudo " + bf_path, shell=True)
print sh.communicate()

Ideally, the script will generate output files, but by executing above code, those files don’t appear, and the “print” result is [None, None]. My guess is that the “Popen” somehow doesn’t get executed at all, or might be that I made a mistake here. So I run above code in python command line, but it turns out that everything works fine. How can that be possible? Please help, thanks.

Answer 1

The reason you are not getting any output from the command is because you have not told the subprocess to open pipes for communication…

from subprocess import Popen, PIPE

sh = Popen("sudo %s" % bf_path, shell=True, stdout=PIPE, stderr=PIPE)

Now communicate will return the output of both stdout and stderr. Also, its possible that the sudo might cause you problems if it requires a password input.