How to set a cron job to run every 3 hours [duplicate] - cron

This question already has answers here:
Running a cron job on Linux every six hours
(8 answers)
Closed 6 years ago.
Is this the correct way for setting a cron job to run every 3 hours?
After setting it this way, cron is executing the command every minute.

Change Minute to be 0. That's it :)
Note: you can check your "crons" in http://cronchecker.net/
Example

Change Minute parameter to 0.
You can set the cron for every three hours as:
0 */3 * * * your command here ..

The unix setup should be like the following:
0 */3 * * * sh cron/update_old_citations.sh
good reference for how to set various settings in cron at:
http://www.thegeekstuff.com/2011/07/cron-every-5-minutes/

Related

Run Cron Job every 5 minutes for 10 seconds

I have a script that I want to run every 5 minutes for 10 seconds.
*/5 * * * * /root/XXX/cronjobs/add-prod.sh
It seems logical to have another cron job that would run every 5 minutes and 10 seconds
that would turn off the 1st cron job.
Something like this:
[FORMULA HERE] /root/XXX/cronjobs/rem-prod.sh
How can we set a formula for "every 5 minutes and 10 seconds" ?
You can do this via timeout. It will kill the process after 10 seconds. It would be better than killing the process externally. Otherwise, jakob22's answer is the best one.
*/5 * * * * /usr/bin/timeout 10 /root/XXX/cronjobs/add-prod.sh
Edit: This is already featured in a comment.

Cron job for 7 days alone not followed by multiple weeks

I need to execute a cronjob to run once for 7 days alone.I have tried like this:
0 0 * * 0-6 myscript.sh
It gets run for once a day and running every day of the week since i gave as 0-6.
But i need to run a job for one week alone not followed by multiple days.I donot want to mention the date of the month,since i need randomly.
(or)
Is it possible through "at" command if it is not through "cron"???
How can i set job to run for 7 days alone guys????
Thanks

Quartz Cron Trigger which fires a job for every 40 seconds [duplicate]

This question already has an answer here:
Cron expression every 50 seconds in Quartz
(1 answer)
Closed 3 years ago.
I faced a weird situation, where I have an only option to use Cron trigger and need to trigger a job for every 40 seconds. Is this possible with Cron trigger. If yes, can you please help.
My expression could go like below:
0/40 * * * * ?
actual result:
job executed at 12:00:00
job executed at 12:00:40
job executed at 12:01:00
job executed at 12:01:40
expected result:
job executed at 12:00:00
job executed at 12:00:40
job executed at 12:01:20
job executed at 12:02:00
Thanks in advance...
in quartz configuration xml file, set <cron-expression> of job definition like below;
<cron-expression>0/40 * * * * ?</cron-expression>
Also, keep in mind that every 40 seconds works like;
fire on 10:00:40
fire on 10:01:20
fire on 10:02:00
...

Is there any way to specify periods with cron without setting up multiple instances?

I want a cron job to run between 7 AM and 10 PM, every day, at 5 minute intervals. Normally this would be okay if it was 5 minute intervals, because you could just use "/5", but is there a way to specify it as 5 minute intervals but skip the times between 10PM and 7AM?
The minutes are specified separately from the hours in crontab. Specify minutes using the periodic notation, and the hours as a range.
*/5 7-21 * * * /path/to/script
Below would help for Quartz scheduler
0 00/5 7-21 * * ?

How do I schedule a cron job to run every hour and a half? [duplicate]

This question already has answers here:
Closed 12 years ago.
Possible Duplicate:
How can I set cron to run certain commands every one and a half hours?
I know that every two hours is:
* */2 * * * command-to-run
but how do I schedule a cron job to run every hour and a half?
You can do this as two cron jobs:
0 0,3,6,9,12,15,18,21 * * * myprog myargs
30 1,4,7,10,13,16,19,22 * * * myprog myargs
This has the advantage of working on even ancient systems that don't support the /2-type syntax.
I think you would need two cronjobs that run every three hours and are offset by 1.5 hours.

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