Answers for "python write sys.stdout to file"

python save output to file

with open("output.txt", "a") as f:
    print("Hello StackOverflow!", file=f)
    print("I have a question.", file=f)

python write subprocess stdout stderr to file

with open("stdout.txt","wb") as out, open("stderr.txt","wb") as err:
    subprocess.Popen("ls",stdout=out,stderr=err)