how redirect output to the file in subprocess.Popen

Question

I tried such code to redirect standart output to the file:

subprocess.Popen('my command', cwd='my path', shell=True, stdout=stdout.txt, stderr=stdout.txt)

But got error: NameError: name 'stdout' is not defined

I use python version 2.5.2

Answer 1

Open the file first and use a to append if you want to keep a record of all output/errors or use w to overwrite each time:

with open("stdout.txt","a+") as stdout:
   subprocess.Popen('my command', cwd='my path', shell=True, stdout=stdout, stderr=stdout)

Using with will automatically close your file.

Answer 2

Give a file descriptor to stdout See doc