Suppose, current time is 11:42 and i have setup one cron file to run at every 5 minutes.
Then this file will run at which time 11:47 or 11:45?
So basically i am trying to understand that how the cron timing is work?
Edit : it was ran at 11:45, but i don't know the reason behind it
Cron Configuration :
*/5 * * * * wget -O /dev/null http://XXX/index.php?r=controller/action
As you know, cron will run jobs at a specific time.
A cron job will not use the time it was started, only the configuration matters. This means a cron job set to every 5 minutes (like your */5 * * * *) will only ever run at times ending with 0 or 5 (eg: 12:00, 12:05, 12:10), regardless of the time you run it. This makes sense because we want to schedule a job for a specific time.
If you really need a job to run every 5 minutes, with an offset (eg: 11:42, 11:47, 11:52) you will have to give a list in the configuration.
instead of (*/5 * * * *) you would need to use:
(2,7,12,...,57 * * * *), filling ... with all the other numbers.
Related
I have configured cron job but it's not working.
I wanted to run the myfile.sh script for every 2 mint and below are my configuration in crontab.
# m h dom mon dow comman
2 * * * * /home/ubuntu/myfile.sh
myfile.sh is executable and contains below lines of code
#!/bin/bash
mysqldump -u[user] -p[password] --single-transaction --routines --triggers --all-databases > /home/ubuntu/backup_db10.sql
Is there anywhere we need to add configure anything?
You're running the script at two minutes past every hour. As in 1:02, 2:02 and so on.
You can change it to something like
*/2 * * * * /home/ubuntu/myfile.sh
to run it every two minutes.
A bit more info can be found here.
I tried to set up the cron job any minute, I tried 3 different commands.
Any of them is not working.
Below is the error:
Run cron job every minute
The syntax is:
* * * * * /path/to/your/script > output
I have a script that I would like to run 60 seconds after initial system reboot and then every 10 minutes after that. I currently need two cron job listings to achieve this:
*/10 * * * * php myscript.php
#reboot /bin/sleep 60; php myscript.php
The first listing will run my cron job immediately after system boot and so I need to have the second listing to account for the on start wait time.
Is there anyway to combine the above two cron listings into one?
I am running a cron job which will run at every 5 minutes.
Now Let's say i have started job on 04:02 so it will execute at every 5 minutes so will execute on 04:07, 04:12, 04:17 etc...
Let's say i have started job on 13:18 so it will executed at 13:23, 13:28, 13:33 etc...
But what i want is it should only execute in multiplication of 5 minutes means if i create job on 04:02, it should start executing from 04:05, 04:10 and so on.
And if start job on 13:18, it should start executing from 13:20, 13:25 and so on.
So how to achieve this?
Try this:
0,5,10,15,20,25,30,35,40,45,50,55 * * * * <Your command>
*/5 * * * *
this should be what you want .
I want to set a cron run after an other cron. For example: Cron A finishs at 01:00 PM, cron B will start at 01:01 PM. The problem is I don't know when cron A finishs.
I checked the crontab syntax. It doesn't provide any param for that purpose.
My actual situation is:
# This cron must run first.
? ? * * * /usr/local/bin/php -f /path/select_and_print_to_log_file.php
# two these crons runs at the same time.
0 13 * * * /usr/local/bin/php -f /path/update_user.php
0 13 * * * /usr/local/bin/php -f /path/update_image.php
# This cron runs right after two above cron completes.
? ? * * * /usr/local/bin/php -f /path/select_and_print_to_log_file.php
You can use the batch command inside the first cron to have the second thing being scheduled to run.
Your first job could produce a timestamp when finished.
Then you estimate - for example - that job A needs about 60 to 90 minutes. After 60 minutes, you start job B. Job b looks for the timestamp. If it is present, job B starts, else it waits for a minute and looks again.
After finishing, job B deletes the timestamp, or renames it, maybe from 'todo' to 'done'. You could insert the current date inside the file, to check, whether your estimation is still acceptable, or should be adjusted.
What I do in such cases (commonly a backup scenario where I don't want to thrash the disk by having concurrent backups) is to write a script that cron calls, and in the script have the actual tasks run serially.
Something like:
#!/bin/bash
/usr/local/bin/php -f /path/update_user.php
/usr/local/bin/someOtherTaskToRunSecond
YMMV.