CODEWITHSUNDEEP
cron
ian
ian

Reputation: 12355

How to set a cron job to run at a exact time?

I have a cron job that runs once a day. But I would like to make it run at midnight or other time exactly.

Upvotes: 74

Views: 177406

Answers (4)

Bruno J. Araujo
Bruno J. Araujo

Reputation: 1503

You can also specify the exact values for each gr

0 2,10,12,14,16,18,20 * * *

It stands for 2h00, 10h00, 12h00 and so on, till 20h00.

From the above answer, we have:

The comma, ",", means "and". If you are confused by the above line, remember that spaces are the field separators, not commas.

And from (Wikipedia page):

*    *    *    *    *  command to be executed
┬    ┬    ┬    ┬    ┬
│    │    │    │    │
│    │    │    │    │
│    │    │    │    └───── day of week (0 - 7) (0 or 7 are Sunday, or use names)
│    │    │    └────────── month (1 - 12)
│    │    └─────────────── day of month (1 - 31)
│    └──────────────────── hour (0 - 23)
└───────────────────────── min (0 - 59)

EDIT:

  • don't miss the 1st 0 (zero) and the following space: it means "the minute zero", you can also set it to 15 (the 15th minute) or expressions like */15 (every minute divisible by 15, i.e. 0,15,30)

Upvotes: 139

Kᴏɴsᴛᴀɴᴛɪɴ Sʜɪʟᴏᴠ
Kᴏɴsᴛᴀɴᴛɪɴ Sʜɪʟᴏᴠ

Reputation: 13066

Very helpful visual constructor

First example cron task:

5 4 * * *

runs at:

04:05

Second example cron task:

5 */1 * * *

runs at:

minute 5 past every hour

Upvotes: 2

Jacques Bezuidenhout
Jacques Bezuidenhout

Reputation: 11

My use case is that I'm on a metered account. Data transfer is limited on weekdays, Mon - Fri, from 6am - 6pm. I am using bandwidth limiting, but somehow, data still slips through, about 1GB per day!

I strongly suspected it's sickrage or sickbeard, doing a high amount of searches. My download machine is called "download." The following was my solution, using the above,for starting, and stopping the download VM, using KVM:

# Stop download Mon-Fri, 6am
0 6 * * 1,2,3,4,5 root          virsh shutdown download
# Start download Mon-Fri, 6pm
0 18 * * 1,2,3,4,5 root         virsh start download

I think this is correct, and hope it helps someone else too.

Upvotes: 1

Brandon Frohbieter
Brandon Frohbieter

Reputation: 18139

check out

http://www.thesitewizard.com/general/set-cron-job.shtml

for the specifics of setting your crontab directives.

 45 10 * * *

will run in the 10th hour, 45th minute of every day.

for midnight... maybe

 0 0 * * *

Upvotes: 35

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