33 */27 * * * python /root/get_top.py
Would the above snippet run every 27 hours and 33 minutes, or every 27 hours starting at 33 minutes past the hour?
If this doesn't make it run every 27 hours and 33 minutes, what is the proper syntax for that?
It doesn't run, because cron supports these ranges:
minutes: 0-59
hours: 0-23
days of month: 1-31
months: 1-12 or Jan-Dec
days of week: 0-6 or Sun-Sat
27 for hours is not supported. Anyhow it doesn't exist the 27th hour in a 24-hours day.
The first field is minutes, so would run at 33 minutes past the hour.
But the next field is the hour field and it is set to run every 27th hour of the day, or in other words, never.
you misunderstand the /, it would mean when the number is dividable by that number, for example */2 would mean every 2 mins because every 2 mins the number is even and is able to be divided by 2.
When you want to create something specific you need to add it manually comma separated, like for example
33 27,54 * * * python /root/get_top.py
Related
I want to execute a crontab every first of month and every sunday, Here is what I think to do, I am not sure if it will execute it the first of month only if it's a sunday or every first of month and every sunday, Any ideas to clarify this are welcome:)
00 16 1 * 7 "command"
Thanks in advance
You are correct, Kahina.
00 16 1 * 7 "command"
will run the "command" at 16:00 on the 1st of each month, plus every Sunday.
I'm trying to write a crontab expression that will begin a specified period of time and run on an interval for a 24 hour period. For example I want the job to run every Thursday beginning at 4 PM and repeat every hour for 1 day. Is there a way to do this? Everything I have tried stops at the end of the day Thursday.
You need two crontab entries, one for the occurrences on Thursday and one for the occurrences on Friday.
For example (I have not tested this):
0 16-23 * * 4 your_command
0 0-15 * * 5 your_command
The fifth column is the day of the week, with Sunday=0. (Vixie cron also lets you specify the day of the week by name.)
i want to set a cronjob in directadmin control panel and i have a question. if i set a job in this format:
05 21 * * * /home/backup.sh
my script will run only one time in a day at 21:05 OR every 5 miutes(12 times in an hour) and every day at 21:00 ?? i want to my cronjobs run's only one time in a day at 21:05! please help me
Your script will run at 21:50 every day.
See the file formats manpage for crontab:
$ man 5 crontab
The line parts before the command for your crontab are: (Below is from the manpage.)
The time and date fields are:
field allowed values
----- --------------
minute 0-59
hour 0-23
day of month 1-31
month 1-12 (or names, see below)
day of week 0-7 (0 or 7 is Sun, or use names)
A field may be an asterisk (*), which always stands for "first-last".
And you will see this example even further below: (Below is also from the manpage.)
# run five minutes after midnight, every day
5 0 * * * $HOME/bin/daily.job >> $HOME/tmp/out 2>&1
man is your friend.
As per the cronjob set by you the first * means minutes, second * means Hour, third * means month, fourth * means day of the month and last * means day of the week. So if you set by
5 21 * * * it would run the job at 9:05pm minutes only.
For more about cronjob check http://www.thesitewizard.com/general/set-cron-job.shtml
Thanks & Regards,
Alok Thaker
Say I have a crontab which runs every 20 minutes and I have a hour range which can vary so lets say a-b, which in one example could look like
*/20 5-23 * * * /usr/bin/cool_program
My question is, will the cron run at 23:00, 23:20, 23:40 and 00:00 too?
GK27's answer does not fully answer the question, so let me clarify:
cron will run jobs when the time matches the expression provided. Your expression tells it to run when the minute is divisible by 20 (*/20) and your hour range tells it to run when the hour is within the specified range inclusively (5-23). The remaining three * tell it to match any day, month, and any day of the week.
Therefore the first job will run at 05:00 because the hour, 05, is in the range 5 to 23 and the minute, 00, is divisible by 20. The last job will run at 23:40 because the hour, 23, is in the range 5 to 23 and the minute, 40, is divisible by 20. It will not run at 00:00 because the hour, 00, is not in the range 5 to 23.
#Alex's answer is correct, however it took me a while to find a source.
The answer is in man crontab.5 (or also info crontab) on Debian, Mac OS X, FreeBSD (and other Posix systems):
Ranges of numbers are allowed. Ranges are two numbers separated with
a hyphen. The specified range is inclusive. For example, 8-11 for
an ``hours'' entry specifies execution at hours 8, 9, 10 and 11.
For my application I wanted a script to run every 5 minutes during business hours (9am - 5pm) and another to run every 5 minutes outside of that. Unfortunately the ranges can't wrap across midnight, so you need to specify 3 ranges (morning, business hours, evening)
*/5 0-8,17-23 * * * outside-hours.sh
*/5 9-16 * * * business-hours.sh
This should run
outside-hours.sh first at 00:00 and finally at 08:55
business-hours.sh first at 09:00 and finally at 16:55
outside-hours.sh first at 17:00 and finally at 23:55
It will execute when minute is divisible by 20 and when hour is in 5-23 inclusive:
* 20 – every 20 minutes from 0 to 59
* 5-23 – 5 to 23 inclusive
* * – Every day
* * – Every month
* * - EvryDay of the Week
The first occurrence is 5:00 and the last 23:40
crontab.guru
Documentation for Reference
What does this command mean in cron? How often will this run? When will it run? Will it run daily?
56 11 * * * /usr/sbin/update-file.sh
From crontab(5):
field allowed values
----- --------------
minute 0-59
hour 0-23
day of month 1-31
month 1-12 (or names, see below)
day of week 0-7 (0 or 7 is Sun, or use names)
Thus, your line means to run /usr/sbin/update-file.sh every day at 11:56 AM.
Crontab format is: minute, hour, day of month, month, day of week, command.
So this will run /usr/sbin/update-file.sh at 11:56 AM every day.