I have several crontab jobs that are executed every minute and I’m thinking on putting “#reboot” jobs. They are put and executed with root privileges.
So here’s what I want to know. Will these cronjobs run when system gets to login screen after rebooting? Will “#reboot” entries run after reboot without me getting logged into root?
Yes, they should run automatically as soon as the cron service gets started. The exact moment can vary depending on the cron implementation and your init system.
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I have scheduled one shell script in cron that fires emails depending on the condition.
I have modified the sender email address.
Now , the issue is while i tested the script in different test environments, somewhere probably it is still active and firing emails from test environment. I have checked crontabs in test environments but nowhere i found out it is scheduled.
Can you guys help me on how to track back where from those emails getting triggered? which instance? which cron etc.
Thanks in advance.
I suggest consulting the cron log file. This file records when and what programs cron starts on behalf of which user.
For FreeBSD this is /var/log/cron. On Linux, as always, it may depend on your distro, the cron implementation, phase of the moon :-) Running man cron might point you at the right file in the FILES section.
I'm new to cron. Someone just introduced it to me. Will cron run for different users?
I mean, I want to run a certain script (which update the database) every 5 minutes if the user is online. What if I have a lot of users who are online? Can cron handle a task like this?
Use crontab -e to edit the current user's crontab. However the script will have to check if the user is online or not.
Cron won't do that automatically.
please can anyone give me a clue on how to Set up a cronjob to execute my API callback URL once every 15 mins, since my control panel does not have that ability, please i need specifications with examples because am still at the armature level, example: i want to setup a cronjop to execute this API call back url http://shop.site.com/modules/cashenvoy/validation.php every 15 mins and my control panel dn't have the option for direct cronjob setting, please how do i go about to setup a cronjob to execute this URL, thanks ur suggestions is appreciated.
Try to use crontab:
# to list current cron jobs
sudo crontab -u username -l
# edit the cron list
sudo crontab -u username -e
This proves a terminal where you can edit the cron jobs.
Insert the following:
*/15 * * * * curl -s http://shop.site.com/modules/cashenvoy/validation.php
This will every 15 minutes silently call the wanted website.
A third party cron job provider may help: http://www.easycron.com.
Disclaimer: I work for easycron.com.
This demo assumes you've already logged in to cPanel
Now let's learn how to setup a cron job
1) Click the Cron Jobs icon
2) Enter the email address where you want the cron job results sent after each time it runs
3) Now you have to define exactly when and how often you want the cron job to run. This is made easier by using one of the pre-defined or common settings
Notice that by choosing a common setting, all fields are filled in automatically. This also helps you understand what each field means
If you have a shared hosting account, crons should not be made more regular than once every 10 minutes.
4) Let's choose Once a week
5) Next, enter the command of the script you want to run, including the path (from root). If you are on shared hosting - add nice -n 15 to the end. This ensures that the server gives the cron a lower priority than critical system processes, helping maintain stability and server uptime.
Remember to add "nice -n 15" to the end of your command!
6) When ready, click Add New Cron Job
That's it! The cron job has been set as you can see here. You can create additional cron jobs, and edit or delete existing ones
This is the end of the tutorial. You now know how to setup cron jobs in cPanel
I defined a cronjob with the whenever gem for Ruby. This created a cron job for the user that runs a ruby script every 5 minutes. The user is not root and doesn't have root permissions.
I would like to be able to run this job randomly between 3-6 minutes. I'm running this job on CentOS 6.2
I think the best thing you could do is setup cron to run the script every minute, and let the script decide when to actually do it's job.
You can have the random effect by keeping track of When the script was executed for the last time
Just make the script run continuously with a random delay between actions. Put it in cron as #reboot and it will restart when the system does.
I'm writing a plugin. It has some job to be execute by wp_cron. Now within the script, it create/edit some posts automatically. So which user will be running the cron job?
Also I notice it failed when calling WP_Filesystem()
Well I've found out that it's running as no one, as get_current_user_id() returns 0
I've been doing some debugging today and I've found that get_current_user_id() is often, but not always, 0 (logged out). The cron can get triggered by any user and your code should anticipate that.