Cron Job

[Cat_4]

I changed my cron schedule from 21:50 to 21:30 last night by crontab -e. However, I found the job run 2 times: one is 21:30 and the other is 22:00.

1. Could anyone tell me why this unexpected cron job run again ?? And why the time is 22:00 ??

2. Is that any guilelines for schedule a cron job ? for example, avoid running different job at the same time ??

thanks in advance.

best regards,
Cat

p.s. My editing time is 21:27, but I don't think they are related ...

[Patrick Wallek]

Can you post the output of 'crontab -l' so we can see what is in the crontab.

Unless you have the job specified twice in cron, there really isn't a way for cron to run it twice.

[Jeremiah Campbell_1]

your crontab entry should look like the following in order to run at 21:30 every night.

30 21 * * * /path/to/job_to_run


I would check for a double entry as well.


HTH
Jeremiah

[Cat_4]

the crontab -l :

30 21 6,10,13,17,20,27 3 * /usr/bin/su -root -c /home/chess32/chess32_mrp

[Jeremiah Campbell_1 · Accepted solution]

that appears to be correct if you want to run the script on the 6th,10th,13th,17th,20th, & 27th of March at 21:30.

I also see that you are doing an su to root, Is this the crontab for an alternate user? If that is the case, then have you checked everyones crontab to ensure that their is not a duplicate in someone elses crontab?

[Patrick Wallek]

You can also have a look at the /var/adm/cron/log file to see what / what started the job at 22:00.

I would also question why you are doing an 'su - root' in the crontab. Why not just run the job from root's crontab?

[Steven E. Protter]

There are no guidelines as to when you run things.

Things to remember.

You have no environment, no path.

If you want to use a utility in your script, use the full path name.

Post the crontab entry, but if it runs when you don't expect it, its probably just a typo.

SEP

[Cat_4]

thanks for all your advice. i should regard this as typo error. Hope it won't be happened again.

Cheers !

[Yogeeraj_1]

hi,

i usually use the following template for my crontabs. This elimates all the risks of any typo errors.

e.g.

#*******************************************************************************
# min|hour |day |month|day |script
# | |of mo| |of wk|
#----|-----|-----|-----|-----|--------------------------------------------------
#*******************************************************************************

#*******************************************************************************
# END OF TABLE day0->Sunday day6->Saturday
#*******************************************************************************


Hope this helps!

regards
Yogeeraj