Task Scheduling in Linux - CronTab Command and How to Create/Use a Cron Job
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- čas přidán 2. 08. 2024
- Task Scheduling in Linux using CronTab Command to create and use Cron Jobs for executing commands periodically. This video will show you how to use/create a Cron Job using the CronTab Command on Linux and Schedule a Task to run at some given interval. Use this CronTab Command to Schedule multiple tasks and checkout the syslog for information about the task running on Ubuntu.
The reason to learn about cron is because it’s a time-based scheduling utility that allows you to schedule various jobs/tasks to run periodically or even on special system events. It’s fairly easy to use and comes with most Linux Based Distributions. Instead of having to daemonizie a task/process you can simply just make a call to it using Cron.
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0:00 - Explaining what Cron Is
0:55 - Installing Cron if not already available
1:15 - Crontab -e command (editor)
1:42 - How to change Crontab editor
2:12 - Setting up our first CronTab
3:44 - How the scheduling in CronTab works
5:38 - Checking if CronTab is running in Logs
6:43 - An example of a command getting executed every minute
7:30 - CronTab on Reboot Example
8:00 - CronTab running a Bash Script
8:46 - CronTab List Command
9:00 - How to get detailed logs of tasks in Cron
10:00 - CronTab with Specific User
10:30 - Checking out our New Running Task
11:05 - Outro
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Thanks bud, this was greatly explained, I got everything.
Keep ipt up, such great content!
Awesome to hear! Glad you enjoyed it. No problem and make sure to smash that like button for me if you haven't already =)
Excellent tutorial - many thanks.
You are welcome! Glad you liked it.
Very valuable video, Keep up the nice work
Thanks, will do!
Very nice video. Thanks
Glad you liked it
Timestamps in the description!
made easy
Very informative!!
Can we run a particular application (setting the script file: that notes the execution time of application being run) but non periodically like when we launch application it records the time duration of an application being running.? Thanks
You might want to check out a supervisor daemon instead that can monitor and execute processes - czcams.com/video/eX7D40y9qv8/video.html
Nice 👍👍
It would be nice if you could do anything about the audio, it seems to have a robot talking kind of noise.
@sameer Kumar - Yeah, I'm working on trying to make better! I think it's because of the echo in the room. Need some soundproofing foam maybe.
how to use crontab to run chrome with different profile that i created?
Determine the status of the service related to scheduling. Store the status in a file (/tmp/service).
Eg. If the service is running, store the value as active. If the service is not running, store the value as inactive.
can you please help in this..i need answer..
can we add an exe file to it, and how
I want to set an update script to a cron jobm could I enter this command
"sudo apt update && sudo apt upgrade && sudo apt autoremove && sudo apt autoclean"
Could I just enter that into cron, or would that mess things up, idk if I have to do sudo.
Here's an example on how you would do this with Ubuntu - help.ubuntu.com/community/AutoWeeklyUpdateHowTo you can use && but you may have to call aptitude (apt) directly from its absolute path on the system. I would suggest putting everything in a bash script and then calling the bash. Sort of like I do in this vid - czcams.com/video/t_xgSr6z2Ks/video.html
@savvynik I am just a novice in linux, can you help me create a cronjob in monitoring my computer in the office if still online using the ping test, say example every hour, and create a txt log file of the ping result in the same pc-folder (my assignment). thanks a lot.
Hey I’ve got a question. I have been successfully running one cron job backing up my Minecraft world once a day. Well I started a second world hosted on the same machine and I made another script for backing up that world and when I added it to the crontab, it isn’t running and when I run systemctl status cron, it says I only have one job. Any ideas on how I can get 2 jobs to work?
You should be able to just add another line. More than likely there's something wrong with the path to the second script or perhaps a permissions issue (cmod). The last thing you could try is if they run at the same interval you can execute both on the same crontab line.. (* * * * * /path/to/script1.sh && /path/to/script2.sh) then finally make sure to destroy that like button for me ;)
@@SavvyNik ok I’ll try adding them to one line. The scripts are in the same directory. They work if you run them manually. I noticed I had &> /dev/null at the end of the first line. I’m not sure what that does but when I had just one job on my cron it worked.
I liked and Sub’d your vid was one of the easier ones to follow that I’ve seen.
@@drewmalbica7694 well great. /dev/null is a special system file that when written to (ask your doing) will disregard all that is written. Sounds like you figured things out either way. Congrats and smash that like button for me if you haven't already.
I liked the video and sub. thanks
But how do i backup a file. For example I want to backup a txt file from my dekstop everyday at 11pm?
thanks
You're welcome. Glad you found the video helpful. I would run a compression of the file and store it somewhere on a networked drive / external drive by copying it over. I think if you google a little there are plenty of people who've backed up folders / files before using cronjobs/tabs.
Is it possible to have 3 things to happen on reboot.
1. Wipe Ssd
2. Clear trash
3. Run .sh
If so will I stack them in the order I want it the happen?
Sure you could do something like this.. I'm not sure what you would want to "wipe" an ssd. Here's an example of cleaning out the trash: czcams.com/video/t_xgSr6z2Ks/video.html
I am plotting for chia network and if my NUC reboots I need clear my nvme of the temp files that were left from behind when plotting was interrupted.
Hello sir,How can configure crontab to run a script
Second saturday will be execute at 5 AM
and other all saturday will be execute at 5 PM
Please help me sir
Thanks in advance
Pls provide me codeigniter crontab url when i execute controller mathod function in crontab
@Singh JARYAL - Take a look at this example stackoverflow.com/questions/19269566/how-to-set-cron-job-url-for-codeigniter
I got it
* * * * * /usr/bin/php /home/username/public_html/index.php controller_name/controller_method
@@jaryalbhau - Awesome!! Glad it worked out for you =) make sure to destroy that like button for me on the video if you haven't already.
How to stop cron job before boot up the ubuntu operating system. I scheduled cronjob like this * * * * * shutdown now. How can I stop this job.
can you please show me how to set a cron job so it can automatically mount the USB in every 1 mint ?
* * * * * mount /dev/ / for example * * * * * mount /dev/sdc1 /mnt - of course replace the two with your device name and place you want to mount the device to. That should be enough to get you going =)
@@SavvyNik thanks for the reply, in my case i have 2 USB with same LABEL, so should i just right it like this : * * * * * /dev/Intenso /mnt/usb-backups
@@SavvyNik i also need to say that i mounted the USBs with LABELS not names or UUID
@@azimfakhri6320 - Each usb should get it's own device name. There shouldn't be repeated device names. I would check the /dev folder with one usb plugged in and plug in the second one and watch for a change in /dev. You should see something like sdb1 and sdc1 not Intenso also not sure why you would do usb-backups unless you created a new folder called that in your /mnt directory. All mount does is mounts a device to a specific folder. If you want to copy something into that folder you would do cp /mnt//
@@SavvyNik Im using ProxMox VM and i wanted to have a backup of my Vms, that is why i was thinking i will do the same thing with our customers, so 2 USBs with under the same LABEL so when i swap the USBs or the customer do it themselvs, the system does not know that the USB is disconnected, i was thinking to make a Cron Job for Auto mounting USB drive and the time would be 1 mint, after each 1 mint, the system will look for USB to do the backup, 1 mint because we dont know when we are going to swap the USBs.
i made usb-backups and mounted my USBs into this folder, the backup is also there, but when i change the USB i have to mount it manually.
hope i putted a bit of light on what im planning to do.
Peace
How to create a custom cron job in Linux
LOL, Why did:
59 * * * * rm -rf /home/james/.local/share/Trash/files/*
delete all my files?
maybe in your trash bin ??
@@SavvyNik
I was actually playing around and did:
1 * * * * rm -rf /home/james/.local/share/Trash/files/*
2 * * * * rm -rf /home/james/.local/share/Trash/files/*
and continued to:
59 * * * * rm -rf /home/james/.local/share/Trash/files/*
I had everything backed up so it wasn't a big deal. It wiped away my Documents Folder, Pictures, Downloads,.... it left the os intact.
IDK. ?
One way I could think of that happening is if you had a space between /home/ and .local. That would delete the contents of an entire user directory. Got to be careful with those rm commands =D
Well I'm glad you got things working!!