I started a cron job on a cluster super computer. I am just a usual user over there and has no root power. The cron job was set by using "crontab -e". It excecutes a perl command every 20 minutes. I could use crontab -l or crontab -r to list or remove the cron job. However, I just found that I could not see the cron job anymore: "crontab -l" or "crontab -e" shows that I have no cron jobs setup. Then I noticed the old cron job is still running: it excecutes the perl command every 20 minutes. The perl command runs fast and there is nothing hanging over. Now, the "crontab -r" does not remove the cron job at all. I can still add new crontab jobs by using "crontab -e", but the old cron job seems to be out of my control.

How can I stop the cron job like this? I know I can change the conrtol file to make the old cron job do nothing, but I still prefer to get rid of it. Any thought on this? Thanks.

I thought you said that "crontab -l" showed nothing?

What can you see in /var/cron/tabs? Is the file with your username non-existant or zero length?

Are you refering to a small wrapper script you use to call the perl program?

I suggest you comment out the call to the perl program or even rename the wrapper. Once you rename, check your mail on the box to see if you start getting mail about not being able to run your job.

If you do, then send that mail plus a listing from "crontab -l" to your administrator.

there is no such a folder "/var/cron/tabs".

yes, I used a wrapper to call the perl program. I have changed the wrapper to make the old cron job do nothing.

I tried to rename the wrapper, but I kept receiving emails complaining about cron daemon failure "No such file or directory".

I guess I have to aks the admin to help me with it.

Thanks.