How to redirect output with subprocess in Python?

Question

What I do in the command line:

cat file1 file2 file3 > myfile

What I want to do with python:

import subprocess, shlex
my         


        

Answer 1

In Python 3.5+ to redirect the output, just pass an open file handle for the stdout argument to subprocess.run:

# Use a list of args instead of a string
input_files = ['file1', 'file2', 'file3']
my_cmd = ['cat'] + input_files
with open('myfile', "w") as outfile:
    subprocess.run(my_cmd, stdout=outfile)

As others have pointed out, the use of an external command like cat for this purpose is completely extraneous.