How to run cron once, daily at 10pm

Question

I had entered:

* 22 * * * test > /dev/null

However, I am being notified via email that this is running every minute. I am confused I guess because I thought this was correct for what I am wanting.

This website will explain any cron schedule: https://crontab.guru/ — Bruno Finger, Sep 28 '17 at 10:22

score 439 · Accepted Answer · edited Jun 03 '19 at 07:01

439

It's running every minute of the hour 22 I guess. Try the following to run it every first minute of the hour 22:

0 22 * * * ....

edited Jun 03 '19 at 07:01

Marv

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answered Jan 20 '12 at 07:37

Marc Simon

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Although the hour 22 might be relatively save, please consider the first case of [this question](https://stackoverflow.com/q/52354269/562769) – Martin Thoma Sep 16 '18 at 12:53
@MartinThoma always try `man cron` first, you should find what you are looking for. – Marc Simon Sep 17 '18 at 15:25
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Remember to check the system's date, it happened to me to set crontab to start a job at 22, but it actually started at 23 because the system was UTC (so 22 for the system was 23 for me in GMT). – nnsense Apr 24 '19 at 18:10
I upvoted this answer but I did know this rule... anyway I wanted to confirm my silent knowledge :D – rnrneverdies May 19 '20 at 00:57

score 189 · Answer 2 · edited Sep 03 '15 at 11:39

189

Here are some more examples

Run every 6 hours at 46 mins past the hour:

46 */6 * * *
Run at 2:10 am:

10 2 * * *
Run at 3:15 am:

15 3 * * *
Run at 4:20 am:

20 4 * * *
Run at 5:31 am:

31 5 * * *
Run at 5:31 pm:

31 17 * * *

edited Sep 03 '15 at 11:39

tripleee

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answered Jan 29 '14 at 18:26

Abdalla Mohamed Aly Ibrahim

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Good examples to understand the cron syntax – Sohel Pathan Aug 10 '20 at 04:42

score 69 · Answer 3 · edited Aug 11 '15 at 07:47

69

To run once, daily at 10PM you should do something like this:

0 22 * * *

enter image description here

Full size image: https://i.stack.imgur.com/BeXHD.jpg

Source: softpanorama.org

edited Aug 11 '15 at 07:47

Peanut

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answered Jan 20 '12 at 07:48

jaypal singh

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Apologies for the bad picture size. – jaypal singh Jan 20 '12 at 08:59

z atef · Answer 4 · 2021-02-15T04:06:21.673

Here is what I look at everytime I am writing a new crontab entry:

To start editing from terminal -type:

 zee$ crontab -e

what you will add to crontab file:

0 22 * * 0  some-user /opt/somescript/to/run.sh

What it means:

[ 
+ user => 'some-user',      
+ minute => ‘0’,             <<= on top of the hour.
+ hour => '22',              <<= at 10 PM. Military time.
+ monthday => '*',           <<= Every day of the month*
+ month => '*',              <<= Every month*
+ weekday => ‘0’,            <<= Everyday (0 thru 6) = sunday thru saturday
]

Also, check what shell your machine is running and name the the file accordingly OR it wont execute.

Check the shell with either echo $SHELL or echo $0

It can be "Bourne shell (sh) , Bourne again shell (bash),Korn shell (ksh)..etc"

Your command shows 0 for the weekday, but your explanation shows it as * — Frak, Feb 14 '21 at 05:59

score 4 · Answer 5 · answered Oct 10 '19 at 18:22

The syntax for crontab

* * * * * 

Minute(0-59) Hour(0-24) Day_of_month(1-31) Month(1-12) Day_of_week(0-6) Command_to_execute

Your syntax

* 22 * * * test > /dev/null

your job will Execute every minute at 22:00 hrs all week, month and year.

adding an option (0-59) at the minute place will run it once at 22:00 hrs all week, month and year.

0 22 * * * command_to_execute

Source https://www.adminschoice.com/crontab-quick-reference

How to run cron once, daily at 10pm

5 Answers5