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

Question

subprocess.call(["/home/myuser/run.sh", "/tmp/ad_xml",  "/tmp/video_xml"])

RIght now I have a script that I run. When I run it and it hits this line, it starts printing stuff because run.sh has prints in it.

How do I pipe this to a text file also? (And also print, if possible)

Answer 1

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.