Python3 - Write to OS pipe /dev/fd/

python3-write-to-os-pipe.py

#!/usr/bin/env python3

# this can be useful in CI environments if you need to process config or secrets and pipe them to the parent process in a secure manner

import io
import os
from time import sleep

w = io.open(69, 'wb', 0)
w.write(b'MY SECRE3T')
w.flush()

# print(os.listdir('/dev/fd/'))

# parent process can read the output like this:
#   python3 test.py 69> test.txt  
# or redirect it to default stdout
#   python3 test.py 69>&1 1>/dev/null