Where do Cron error message go?

Question

I have a python script running by cron. For what ever reason, it is not running. I am wondering if there is anywhere that error messages are sent? Script runs fine by itself. If I run a simple script with crontab, that just writes to a file that works also.

My crontab is:

*/15 * * * * python ./home/pi/foo/bar.pyw

• Richard: Ok, I figured out the issue with my script. I was calling modules which were in the same directory as the bar.pyw script. I changed the working directory with os.chdir("some location"). I still however would like to know where the error messages go for crontabs

Answer 1

By default, the logging for the cron daemon is not enabled in Debian (I assume it is the system you are using). To enable it, please open the file /etc/rsyslog.conf via

$ vi /etc/rsyslog.conf

and uncomment the line

# cron.* /var/log/cron.log

After that, you need to restart rsyslog via

$ /etc/init.d/rsyslog restart

and you will find the cron logs in /var/log/cron.log

Source: Enable crontab logging in Debian Linux

• Bex: Alf: Thank you for your reply. I have now implemented cron logging and have alter the command in my crontab to [Code] */3 * * * * /usr/bin/sudo -H /home/pi/ahbc [/code] The sudo -H is something I found on the web which I am told works. I don't understand just what the -H is there for. I have been given to understand that if one does not include the uservin a crontab command line that command will run using the user/owner of crontab. Therefore as my crontab is user pi crontab the contained commands will run for pi.
• Michael: the link is broken now :(
• Morgan Courbet: @Michael The explanation here should be enough to achieve logging. Do you need something else?
• SiKing: @ElanHasson Anything that generates extra writes to the SD card and is a low priority is generally disabled on the rPi.
• Kioshiki: I've just posted an edit request for the link, it looks like the source site just changed it's setup a bit.

Answer 2

Crontab has several parameters (in additional to time execution lines) For example:

MAILTO="[email protected]"
SHELL="/bin/bash"