Python: copy file tree to a text file - python-3.x

Question

I'm trying to create a text file with a tree of all files / dirs from a place that I choose using os.chdir(). My approach is to print the tree and to save all prints to the text file. The problem is that it doesn't copy the printed tree and the file is blank.
What am I doing wrong?
And is there a way to write this kind of data to the file without to actually print it?
My code:
import os
import sys
f = open("tree.txt", "w")
os.chdir("c:\\Users\Daniel\Desktop")
sys.stdout = f
os.system("tree /f")
f.close()
Edit
I was able to get the file tree from the clipboard after executing the command, however it gives me and eror when it tried to write to the txt file.
code:
import os
import tkinter
with open("tree.txt", "w") as f:
os.system("tree /f |clip")
root = tkinter.Tk()
tree = root.clipboard_get()
print(tree)
f.write(tree)
eror:
Traceback (most recent call last):
File "c:\Users\Daniel\Desktop\Tick\code_test\files.py", line 9, in <module>
f.write(tree)
File "C:\Users\Daniel\AppData\Local\Programs\Python\Python38-32\lib\encodings\cp1252.py", line 19, in encode
return codecs.charmap_encode(input,self.errors,encoding_table)[0]
UnicodeEncodeError: 'charmap' codec can't encode character '\u2502' in position 80: character maps to <undefined>
solution
So I found the problem, I needed to use codec to be able write unicode to the text file. Now it works very well
code:
import os
import tkinter
import codecs
with codecs.open("tree.txt", "w", "utf8") as f:
os.chdir("c:\\Users")
os.system("tree /f |clip")
root = tkinter.Tk()
tree = root.clipboard_get()
f.write(tree)

Answer 1

Method check_output from subprocess module can help you to catch program output:
import subprocess
f = open("tree.txt", "wb")
tree_output = subprocess.check_output('tree /f', shell=True, cwd=r'c:\Users\Daniel\Desktop')
f.write(tree_output)
f.close()
Or with context manager:
import subprocess
with open("tree.txt", "wb") as f:
f.write(subprocess.check_output('tree /f', shell=True, cwd=r'c:\Users\Daniel\Desktop'))
Option wb is required because check_output returns bytes not a str. If you want to process output like a string - call tree_output.decode() first.