[SOLVED] Cannot redirect crontab output to file

Issue

I am on a raspberry pi 5 model B rev 1.0, and am trying to redirect the contents of this simple python program to a file:

import time
import sys

while True:
    time.sleep(1)
    sys.stdout.write("out\n")
    sys.stderr.write("err\n")

I then added this run statement via sudo crontab -e:

@reboot /usr/bin/python3 /home/pi/test.py >> /home/pi/cronlog.log

However, after restarting my computer, the only logs that I see in cronlog.log are the "err" logs.

I also tried this variation:

@reboot /usr/bin/python3 /home/pi/test.py >> /home/pi/cronlog.log 2>&1

and also even tried specifying the log file specifically:

@reboot /usr/bin/python3 /home/pi/test.py >> /home/pi/cronlog.log 2>> /home/pi/cronerr.log

Neither worked, only printing out the "err" message into the cronlog.log file.

As a last resort, I tried:

@reboot /bin/bash -c "/usr/bin/python3 /home/pi/test.py >> /home/py/cronlog.log"

And... it still only printed out the err logs.

Any help? Thanks!

As a note, I have tried all of these commands in my normal bash instance, and they work perfectly as expected.

Solution

Thank you to @larsks for providing this solution.

The issue was fixed I added a -u after the python3 command. (for unbuffered)

python3 -u test.py > file.txt

Answered By - unfestive chicken

Answer Checked By - David Goodson (WPSolving Volunteer)