Cron is used to execute scheduled commands. It acts as a task scheduler on Linux and UNIX systems which will execute commands at specified times set by the user. Cron has a great deal of customization and is often used on server environments where common tasks are run on a regular basis.

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11
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5answers
7k views

Generic solution to prevent a long cron job from running in parallel?

I am looking for a simple and generic solution that would allow you to execute any script or application in crontab and prevent it from running twice. The solution should be independent on the ...
3
votes
4answers
2k views

Cron not able to succesfully change background

I'm running 12.04 with a custom XML background (modification on Day of Ubuntu) that changes based on time of day. I've noticed that there's a significant delay between when the changes are scheduled ...
-1
votes
2answers
19k views

Crontab not working

I know that this was asked several times, but I don't know what to do... I've tried all the solutions proposed on AskUbuntu, but with no results... So... I have this shell script in my home ...
2
votes
1answer
816 views

Cron job not executing?

I'm trying to execute a PHP script every two minutes on my server, but it doesn't seem to be working. I'm using the following cron job: 2 * * * * /usr/bin/php ...
1
vote
2answers
5k views

Mutt runng from Crontab

I have a bash script that is sending an email through command line mutt. This bash script is being called from a cron job (setup using crontab -e because of permissions needed to do all items in the ...
3
votes
2answers
782 views

Taking timely screenshots of particular sites

I have a website where I have to take weekly screen shots of sister sites. I was wondering how this maybe done. I had obtained the code for taking screen shots but have no idea how to open up the ...
1
vote
1answer
4k views

Run Java application as Cron job

I've tried everything I can think and searched high and low for solutions of but I can't get JAVA_HOME into cron to run anything java periodically. In terminal java -version gives me everything ...
0
votes
1answer
5k views

Cron not running scripts

I have looked for several reasons that could cause my problem without luck. The issue seems to be extremely particular: my server running LTS 10.04 is not correctly running scripts relating to ...
0
votes
1answer
128 views

Is there a way to schedule aptd to check for updates only at certain times?

On Ubuntu 12.04 I've noticed that aptd sometimes uses 100% of a CPU and tends to slow down my whole laptop. I wasn't installing any packages so I'm assuming that this is the automatic update check. ...
1
vote
0answers
581 views

Is wake up from standby possible via script or schedule? [duplicate]

Is it possible to cause Ubuntu to resume from standby or sleep mode to run a scheduled task like at job/crontab? (hibernation seems to be ruled out in another question) Can a script be written that: ...
2
votes
1answer
2k views

How to check when was the last time anacron successfully run?

How can I check when was the last time anacron completed all the daily/weekly/monthly jobs? I understand that the timestamps at /var/spool/anacron are the times anacron started, but it can be that the ...
3
votes
1answer
976 views

Run /etc/cron.daily/apt at a specific time (i.e. without anacron)

I want to setup a cron job to download up-to-date package only at night. But I found that the cron.daily jobs will be run by anacron if it's installed, so if my computer fails to wake-up at night to ...
3
votes
1answer
435 views

Good workflow for updating R modules around R-cran updates?

I like that R updates frequently to give me the best new packages, but it does seem to pose a problem for my R scripts on cron schedules. I noticed that every time ubuntu updater updates my r-base ...
0
votes
1answer
280 views

Why does mplayer freeze when running from Scheduled Tasks?

I've been trying to use Scheduled Tasks and mplayer as an alarm clock, scheduling mplayer /path/to/file.mp3 for my morning wakeup time, but whenever it reaches the scheduled time, mplayer freezes only ...
4
votes
1answer
2k views

run .profile function as cron job

In the .profile file of the root user I have defined a function, e.g. function printDate() { date } I want to run this function every minute and append the output to cron.log. I tried adding the ...
14
votes
2answers
74k views

Script doesn't run via crontab but works fine standalone

I have a script that reminds me to restart my computer if uptime is more than, say 3 days (although its set to 0 days now just to check if the script is running as my computer has been up only over a ...
0
votes
3answers
1k views

Crontab -e gives me error messages

I get a bunch of error messages when I run crontab -e Here are the error messages. And here is my crontab file under `/usr/bin/': # /etc/crontab: system-wide crontab # Unlike any other crontab you ...
4
votes
3answers
265 views

Do I have to set up mail for Ubuntu to be able to mail users?

I remember Debian automatically sending mail to users (to report a failed sudo authentication attempt, for example). On Ubuntu is mail of some kind automatically set up? I created a cron job, and ...
5
votes
1answer
712 views

What is the easiest way to set up a cron job?

Every time I set up a cron job there is something wrong with it and I spend a lot of time trouble shooting it. I use Ubuntu and I would like to know what tools exist to make my life easier when ...
6
votes
3answers
11k views

Daily cron job not running

A quick overview: I have a script that will daily backup my source code repository from SVN into a tarball for that day. I have tested the script and it works very well as long as I run it as sudo, ...
1
vote
1answer
334 views

Scheduled tasks won't start

I am quite new to the world of Ubuntu (11.04 is my version), so please bear with me if I do not give all the necessary details to help you help me. I constantly record radio streaming on the Internet ...
3
votes
2answers
2k views

Why is git not using my pubkey with crontab?

To backup my sql database I have a cron job running that makes a mysql dump. Now I want to create another cron job that commits this dump to the repo, the problem now is that it doesn't work. In the ...
2
votes
2answers
2k views

crontab command not run

I'm trying to get execute a cron job everyday at noon but i can't get it to run. To test it i even tried something like a simple create command but it never runs, it seems as if the file isn't even ...
1
vote
1answer
56 views

at job facility for anacron?

Is there a tool for Ubuntu to schedule jobs similar to at but for anacron instead if plain cron? Eg. echo "rm -Rf /tmp/workdata.$$.*" | at now + 99 minutes It doesn't have to be via anacron, just ...
1
vote
1answer
542 views

Managing cron.*

I see that Ubuntu uses /etc/cron.{daily,weekly,monthly} for cron jobs. I also see that some things, like updatedb from mlocate, put their jobs there: $ dpkg -L mlocate|grep y/m ...
2
votes
1answer
391 views

Is it necessary to monitor cron/anacron?

I use Ubuntu at home for my personal matters, not as a "server". I shut down my computer two or three times a day and there aren't any fixed usage times. I understand that there are automated tasks ...
5
votes
2answers
2k views

NMCLI works in script when I run itdirectly , but not when run in CRON

This is under Ubuntu 11.10 I have a script that starts a PPTP VPN connection fetches a couple of files, then closes the connection. When I run this script from a terminal prompt it works perfectly; ...
1
vote
2answers
254 views

How can I automate the backing up of cron jobs?

In the even of a crash I realize that I may not be backing up system and user cron jobs. How can I automate the backing up of my systems cron jobs?
2
votes
1answer
206 views

Script not working through Cron - JDK version mismatch between shell and script

I am executing a script through cron using the below command: */10 * * * * cd /nas/app/someFolder/psox; ./RunPSOX.sh >> /tmp/trial.log 2>&1 This is being executed by root user. All ...
2
votes
3answers
1k views

What is the easiest, most effective backup system for Ubuntu Servers?

I'm trying to backup my /var/www/ folder, MySQL, and any other special documents like in the /etc/apache2/ folder. Does anyone have any solutions for backup software? Maybe something that's ...
1
vote
1answer
1k views

How to run gui app from cron as root?

The following works in cron: * * * * * non-root-user export DISPLAY=:0.0; zenity --info And displays a zenity dialog on non-root-user's desktop each minute. But if I do the following: * * * * ...
0
votes
1answer
482 views

Crontab Output problem

I have this script. When I run it from the command line, it works fine. When I run it from cron, it only prints out half of the data The results should look like this: 07/Feb/2012 11 0.5 ...
0
votes
1answer
3k views

how to kill a cron job if it doesn't show in ps? or get it to show in ps?

I have a cronjob set up like so: ~> crontab -l 0 * * * * /bin/bash -l -c 'cd /mnt/hgfs/kodiak && RAILS_ENV=test bundle exec rake nightly_tasks --silent 2>> ...
4
votes
3answers
2k views

cron jobs not running

I've got a couple of scripts that I've had scheduled to run in cron for a while. About a week or so ago, they stopped running as far as the (very basic) logging showed, and also I noticed that my ...
3
votes
0answers
211 views

Error from Ksplice cron job [closed]

I'm running Ksplice on Ubuntu 11.10 64 bit and I get the following error when the Ksplice cron job runs. $export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin && [ -x ...
0
votes
1answer
110 views

Crontab file is garbled! HELP!

I accidentally deleted my .bashrc file in Ubuntu 11.10. I think I restored it but I have two major issues now: Everything that I type has a red squiggly line under it in this field and the ...
0
votes
2answers
470 views

Linux set time from net at login

On my Ubuntu 10.04 box I (a user, not root) can issue sudo net time set and it works great. I'd prefer that the box get the net time on a more regular basis, or at least each time it gets logged ...
1
vote
1answer
364 views

Run anacron even when on battery (laptop)

There is a known behavior of anacron not to run when the laptop is running on batteries. Is there any way to stop this behavior and run anacron whatever the power state? ...
9
votes
3answers
27k views

Cron Job Not Running?

I have a crontab file that looks like this: * * * * * /home/abliskovs/update/update.sh However when I check the syslog for evidence that the job has run, there is nothing that might indicate that it ...
0
votes
1answer
905 views

How to restart anacron every hour?

What is the proper way to restart anacron? I want to set it up to restart every hour. Would a crontab entry like do the job? sudo crontab -e @hourly anacron Why is anacron initially started by ...
3
votes
3answers
5k views

TIme of execution of daily anacron job

I have set a daily anacron job, which runs form /etc/cron.daily. From the /etc/crontab I see it should run daily at 06:25 (or at start-up/reboot). However when the date changes (00:00) and the ...
3
votes
2answers
738 views

Where can I find a PPA for fcron?

According to https://launchpad.net/ubuntu/oneiric/+package/fcron it seems that there is a version of fcron available for 11.10, but reffering to http://www.ubuntuupdates.org/packages/show/329892 it ...
0
votes
1answer
185 views

“aptitude update” as cronjob, customize the cron-mail-output

I have set up aptitude update as cronjob for root and sending the mail to my normal user account. What I want to have now, is that all the output of aptitude is ommited and instead only a ...
2
votes
1answer
858 views

cron.weekly does not run

I have a shellscript in /etc/myprog/myscript.sh that I would like to run every week. Therefore I created a symbolic link in /etc/cron.weekly: root@ip-10-190-199-197:/etc/cron.weekly# ls -ltr total 8 ...
6
votes
2answers
4k views

How to run a script only once per day with cron without specifying execution time

I wan to run a backup script once per day but i dont want to specify a certain time, just once per day. I've read that the @daily cron attribute runs every day at 00:00 but i don't know if the ...
0
votes
1answer
243 views

Cron Job and permissions

I have set a cron job to execute a bash script. If I change the permissions of the script to (Others: None) will it still be executed? Thanks a lot
2
votes
1answer
3k views

Safe adding and removing cron jobs from shell script?

I need to create a package, which should add itself to list of cron jobs, and remove it from that list on deinstallation. How can I do it without possibility of screwing the crontab file? Maybe there ...
2
votes
1answer
2k views

Does Ubuntu periodically clean empty directories under /var/run?

I've noticed that empty directories get deleted from /var/run/ on reboot. I'm wondering if that's something Ubuntu does or something that I have installed.
0
votes
3answers
1k views

Scripts in crontab don't get executed at all

i did something as simple as this: crontab -e * * * * * touch /home/alexis/hi.txt crontab: installing new crontab but it doesn't work at all; not mentioning more complicated scripts. any idea ...
6
votes
2answers
3k views

Keep getting mails about xdebug

I'm running Oneiric as a LAMP development server, and have xdebug installed. It works fine, but since I set up my email so that root mails are forwarded to my gmail, I keep getting the following: ...