How can I test my crontab? Is there a command I can run to test it?

What kind of test? Here's some things I do...

• Is cron running? ---> Run ps ax | grep cron and make sure it shows up!
• Is cron working? ---> Try: * * * * * /bin/echo "foobar" >> /file_you_own and make sure it works.
• Is your command working? ---> Try: * * * * * /bin/foobar > /file_you_own 2>&1 and look for errors in /file_you_own
• Can cron run your job? ---> Check the cron log, usually /var/log/cron.log or /var/log/messages for errors

It is very easy. All you have to do is think logically

1st place to look is in the logs.

On Redhat, and variants, the file to examine is /var/log/cron I am not sure about its whereabouts on Debian, but I'd suspect it's pretty much the same.

Try

To see the last few lines of that file.

That file is basically a list with the times and commands that cron executed.

Another option would be to add a line to your crontab like this

If your cron works, then after two minutes, you will see the word test appear on your console every minute

For me under Ubuntu 11.04, "wall test" failed. This worked, though


And then look for tile /tmp/cronworked.txt

Under Ubuntu, if it did NOT work, errors are in /var/log/syslog

An article explaining the Linux cronjob scheduling with the help of examples.

http://www.thegeekscope.com/linux-cron-job-scheduler/

Hope you will find this post useful !