I wrote this small Python script to make daily backups of a directory containing some files (the backups should rotate after one week). This is it:

$ cat /etc/cron.daily/file-store-backup.py

import datetime
import calendar
import subprocess
import os.path

def main():
    origin = '/var/file-store'
    today_name = calendar.day_name[datetime.date.today().weekday()]
    dest = '/var/file-store-backup/' + today_name

    if os.path.exists(dest):
        subprocess.call(['rm', '-rf', dest])

    subprocess.call(['cp', '--reflink=always', '-a', origin, dest])
    subprocess.call(['touch', dest])

    last = open('/var/file-store-backup/LAST', 'w')
    print(today_name, file=last)

if __name__ == "__main__":

when I run it manually, it works as expected, creating a backup directory named after current week's day, but it is not being run daily: I left it inside /etc/cron.daily for 3 days and after that no backup directory was created, the server was on all time.

The permissions are right:

$ ls -l /etc/cron.daily/file-store-backup.py 
-rwxr-xr-x 1 root root 553 Abr 11 17:19 /etc/cron.daily/file-store-backup.py

The system is Ubuntu Server 12.04.2 LTS and the cron configuration was not tampered with since installation.

Why the script is not being run?

  • check /var/log/cron.log and search for the script name - file-store-backup.py and see if there are any errors in the cron log.
    – Daniel t.
    Apr 15, 2013 at 21:26

2 Answers 2


This is happening because your script has a .py extension. The files in /etc/cron.daily are run by the run-parts(8) command and it's default is to ignore programs that don't match various rules. You should be able to just remove the .py extension.

run-parts runs all the executable files named within constraints described below, found in directory directory. Other files and directories are silently ignored.

If neither the --lsbsysinit option nor the --regex option is given then the names must consist entirely of ASCII upper- and lower-case letters, ASCII digits, ASCII underscores, and ASCII minus-hyphens.

For example

touch /etc/cron.daily/test.py
chmod +x /etc/cron.daily/test.py
run-parts --test /etc/cron.daily

no sign of test.py

mv /etc/cron.daily/test.py /etc/cron.daily/test
run-parts --test /etc/cron.daily 

ta da !

  • the run-parts --test /etc/cron.d is a life-saver, forgot the chmod +x :/
    – hotzen
    Oct 15, 2018 at 18:41

Shouldn't the cron entry look like 0 * * * 1-7 root /etc/cron.daily/file-store-backup.py

I don't usually put the actual script in the cron file, usually I refer to the script in the file.

  • 2
    Take a look in /etc/cron.daily and be educated.
    – user9517
    Apr 15, 2013 at 21:17

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