How do I schedule a cron job to run every 6 hours, which should start at a particular time?

[varad_joshi]

I need to start a cron job where I am setting up alerts every 6 hours using * */6 * * * in cron. However I want first alert to get triggered at a particular time. where do I set that?

This could be fairly simple, a newbie here 🙂

[FritzWittwer_ol · Accepted solution]

or you can just use commas:

57 1,7,13,19 * * *

Means on the 57th Minute of the hours 1, 7, 13 and 19

[varad_joshi]

Like I said it could be fairly simple. One of the colleague @meenal901 also suggested.
Thanks this was helpful.

[lloydd518]

I don't think cron can quite meet your requirement but I have produced a couple of examples where we can try and manipulate cron which may help you solve your problem..

57 7-23/6 * * *

This schedule runs on the 57th minute of the the hour - between 7am and 11pm every 6 hours... So in splunk it fires at 7:57 13:57 19:57 And back to 7:57 the next day...

00 1-23/6 * * *
This schedule runs at the start of the hour 00min between 1am and 11pm every 6 hours.... So in splunk it fires at 01:00 07:00 13:00 19:00 And back to 01:00 the next day...

00 5-24/6 * * *
This schedule runs at the start of the hour 00min between 5am and 12am every 6 hours.... So in splunk it fires at 05:00 11:00 17:00 23:00 And back to 05:00 the next day...

So this may help you but it can end up missing a period as in the first example which only fired 3 times as opposed to the next 2 examples which fired off 4 times...

Hope this helps...

lloydd518