How to make a call to an executable from Python script?

Question

I need to execute this script from my Python script.

Is it possible? The script generate some outputs with some files being written. How do I access these files? I have tried with subprocess call function but without success.

fx@fx-ubuntu:~/Documents/projects/foo$ bin/bar -c somefile.xml -d text.txt -r aString -f anotherString >output

The application "bar" also references to some libraries, it also create the file "bar.xml" besides the output. How do I get access to these files? Just by using open()?

Thank you,

Edit:

The error from Python runtime is only this line.

$ python foo.py
bin/bar: bin/bar: cannot execute binary file

Answer 1

The simplest way is:

import os
cmd = 'bin/bar --option --otheroption'
os.system(cmd) # returns the exit status

You access the files in the usual way, by using open().

If you need to do more complicated subprocess management then the subprocess module is the way to go.

Answer 2

For executing the external program, do this:

import subprocess
args = ("bin/bar", "-c", "somefile.xml", "-d", "text.txt", "-r", "aString", "-f", "anotherString")
#Or just:
#args = "bin/bar -c somefile.xml -d text.txt -r aString -f anotherString".split()
popen = subprocess.Popen(args, stdout=subprocess.PIPE)
popen.wait()
output = popen.stdout.read()
print output

And yes, assuming your bin/bar program wrote some other assorted files to disk, you can open them as normal with open("path/to/output/file.txt"). Note that you don't need to rely on a subshell to redirect the output to a file on disk named "output" if you don't want to. I'm showing here how to directly read the output into your python program without going to disk in between.