How do I pipe a subprocess call to a text file?

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 written to a file)

You need to open a file with something like open and pass the object or file descriptor integer to call:

f = open("blah.txt", "w")subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml",  "/tmp/video_xml"], stdout=f)

I'm guessing any valid file-like object would work, like a socket (gasp :)), but I've never tried.

As marcog mentions in the comments you might want to redirect stderr as well, you can redirect this to the same location as stdout with stderr=subprocess.STDOUT. Any of the above mentioned values works as well, you can redirect to different places.

The options for popen can be used in call

args, bufsize=0, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=False, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0

So...

myoutput = open('somefile.txt', 'w')subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml",  "/tmp/video_xml"], stdout=myoutput)

Then you can do what you want with myoutput

Also, you can do something closer to a piped output like this.

dmesg | grep hda

would be:

p1 = Popen(["dmesg"], stdout=PIPE)p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)output = p2.communicate()[0]

There's plenty of lovely, useful info on the python manual page.