Unlike some other Linux distributions, Ubuntu doesn't create a dedicated /var/log/cron file by default. The cron service logs through rsyslog, and you'll typically find cron-related messages in the main system log:

sudo grep CRON /var/log/syslog


First verify that the cron service is actually running:


# For systems using systemd
systemctl status cron

# Older systems using init
service cron status


You should see output indicating the service is active (running). If not, start it with:

sudo systemctl start cron


To enable more detailed logging, edit the rsyslog configuration:

sudo nano /etc/rsyslog.d/50-default.conf

Uncomment or add this line:

cron.* /var/log/cron.log

Then restart the services:


sudo systemctl restart rsyslog
sudo systemctl restart cron



For individual cron jobs, you can redirect output to log files in the crontab itself:


* * * * * /path/to/script.sh >> /var/log/my_cron.log 2>&1


Or use logger to send messages to syslog:


* * * * * /path/to/script.sh 2>&1 | logger -t my_cron_job



1. Check for environment differences - cron runs with a minimal environment:


* * * * * env > /tmp/cron_env.log


2. Verify permissions on scripts and log files

3. Test commands manually using the same user context:

sudo -u [username] [command]

4. For mail-related issues (cron sends output via mail by default):

sudo apt install postfix


For security-conscious environments, configure auditd to track cron execution:


sudo apt install auditd
sudo auditctl -w /usr/sbin/cron -p x -k cron_execution
sudo ausearch -k cron_execution | aureport -f -i




Unlike some other Linux distributions, Ubuntu uses syslog for cron logging by default. The main locations to check are:

/var/log/syslog
/var/log/cron.log  # If rsyslog is configured for cron

First check if the cron daemon is active:
sudo systemctl status cron

You should see output like:
● cron.service - Regular background program processing daemon
     Loaded: loaded (/lib/systemd/system/cron.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2023-05-10 09:25:33 UTC; 1h ago

If you're not seeing cron logs, you may need to enable them in rsyslog:
sudo nano /etc/rsyslog.d/50-default.conf

Uncomment or add this line:
cron.*  /var/log/cron.log

Then restart the services:
sudo systemctl restart rsyslog
sudo systemctl restart cron

To verify your crontab entries:
crontab -l

For system-wide cron jobs, check:
ls /etc/cron.*/
cat /etc/crontab

Add logging to your cron jobs for better debugging:
* * * * * /path/to/script.sh >> /var/log/my-cron.log 2>&1

Or redirect output to syslog:
* * * * * /path/to/script.sh | logger -t mycron