Fix Python – How to redirect output with subprocess in Python?


Asked By – catatemypythoncode

What I do in the command line:

cat file1 file2 file3 > myfile

What I want to do with python:

import subprocess, shlex
my_cmd = 'cat file1 file2 file3 > myfile'
args = shlex.split(my_cmd) # spits the output in the window i call my python program

Now we will see solution for issue: How to redirect output with subprocess in Python?


UPDATE: os.system is discouraged, albeit still available in Python 3.

Use os.system:


If you really want to use subprocess, here’s the solution (mostly lifted from the documentation for subprocess):

p = subprocess.Popen(my_cmd, shell=True)
os.waitpid(, 0)

OTOH, you can avoid system calls entirely:

import shutil

with open('myfile', 'w') as outfile:
    for infile in ('file1', 'file2', 'file3'):
        shutil.copyfileobj(open(infile), outfile)

This question is answered By – Marcelo Cantos

This answer is collected from stackoverflow and reviewed by FixPython community admins, is licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0