Cron is a job scheduler that allows users to run commands periodically.

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need portable crontab host-checking/failover logic across Linux & Cygwin

A host-ping test that always works correctly from the interactive bash command line in Cygwin, is behaving incorrectly in its own crontab--always selecting the second host--and I can't figure out why: ...
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2answers
760 views

Is there anything in unix crontab to determine this should be executed in PST/CST standard time?

There is this thing in QuartzScheduler where we can say execute this in CST/BST/ or whatever timezone. This is also good when you want to execute some jobs in certain timezones and certain jobs in ...
3
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3answers
2k views

How to schedule something run once using anacron?

Frequently within my scripts I schedule auxiliary tasks for later in the form: at now + 8 hours <<< "rm -f workfile.$$ >> $worklog 2>&1 " or at 11pm + $(date +%M) minutes ...
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1answer
80 views

Setting up a cronjob as a file

I want to create a cronjob at my Ubuntu server by adding/modifying a file in the /etc/cron.d folder, rather than using crontab -e as it's not too easy to automate. I've managed to make a file looking ...
2
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2answers
609 views

changing default shell to /bin/bash of at job scheduler like in CRON

I recently switched from 2>&1 >> to &>> Is there a way to have at use /bin/bash as the shell? By default it uses /bin/sh and the man page gives no indication how anything else ...
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0answers
395 views

Facing issue with cron on embedded linux

I have a SAM9 based board running embedded linux using buildroot package. I added the crond and crontab support to busybox from make menuconfig and built the rootfs and flashed it to my board. The ...
11
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1answer
1k views

What does the following kernel message mean?

The following appears /var/log/messages, what that means ? Feb 19 22:51:20 kernel: [ 187.819487] non-matching-uid symlink following attempted in sticky world-writable directory by sh (fsuid ...
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1answer
202 views

Crontab Change location

I want to set a personal crontab in another folder and executed. For example I want it in /home/project/tasks/crontab Like that it's easier to add/delete tasks. Thank you for your answers.
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3answers
2k views

Frustrating issue where neither cron nor su -c runs my job (permissions?)

Updated (and snipped) with more details below. I've set up a cron script and I'm trying to debug why it's not running. [Snipped context testing, which is all ok; see revision 2 for details] The ...
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4answers
1k views

command for counting number of active cron jobs in crontabs

Problem statement I have 5 solaris boxes, some have Solaris 10 and some have Solaris 9. All of them have many cronjobs in their crontabs. I would like to know number of active cronjobs available, so ...
2
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2answers
687 views

Is crontab related to server performance?

I am using Solaris 10, and I am adding many cronjobs to my server's crontab. Currently I have 30 cronjobs in my crontab. one cronjob takes 8 hours to complete ,one other cron job takes 5 hours to ...
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2answers
2k views

Origin of the word cron?

Trying to settle a friendly argument. Is "cron" an acronym for something? Additionally, did it's current canonical name "cron" originate from something shortened for something like chronos or ...
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2answers
1k views

cifs write errors in cron job

EDIT: THE SOLUTION With Tim's help I determined that larger writes of data were failing versus smaller ones. Why they didn't fail when I ran the script interactively, I don't know...But here was the ...
5
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2answers
2k views

Open emacs in a terminal when editing crontab

I have setup emacs as my default editor in /etc/profile. When I want to use emacs in a terminal. I open it with the -nw option. How can I have the same behavior when doing a crontab -e preventing it ...
2
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2answers
6k views

List currently running cron tab and stop it

I created a cronjob, it runs for a very long time but now don't know how to stop it. Please help.
6
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1answer
4k views

Meaning of “* */1 * * *” cron entry?

Somehow, I am finding it difficult to understand tweaking around * parameters with cron. I wanted a job to run every hour and I used the below setting: * */1 * * * But it does not seem to do the ...
4
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2answers
5k views

How can I know when a cron job was killed or it crashed?

Usually when a cron job crash, it will leave some error messages in the log. We run shell script and some java program with cron job. Recently we found some weird thing out from the log. Obviously ...
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1answer
141 views

Can I filter how often cron emails me?

I have a few cronjobs and one of them is run every minute. I had to take a website down for two hours and it caused an error on that one specific cronjob and I got almost 120 emails in those two hours ...
2
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4answers
837 views

Is there any handy command line tool to manage Cron jobs?

Would someone suggest any handy command line (NOT web) tool or script which adds, enables and disables Cron jobs? I am looking, for example, for the following (or similar) behavior: sh manageCron.sh ...
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2answers
10k views

Can I change the default mail recipient on cron jobs?

I believe that if there is any output from a cronjob it is mailed to the user who the job belongs to. I think you can also add something like MAILTO=vivek@nixcraft.in at the top of the cron file to ...
1
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1answer
847 views

grep searchstring /etc/crontab strange behavior in BASH script

I am working on a BASH script which creates automated backups via the crontab. I am trying to use myVARIABLE=`grep backup /etc/crontab` to return lines containing "backup" if an entry has already ...
12
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1answer
5k views

How do I enable locate and queue the database to be built?

On a new Ubuntu 10.4 instance, I tried to use the locate command only to receive the error locate: can not stat () `/var/lib/mlocate/mlocate.db': No such file or directory from using this command ...
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1answer
74 views

App which can execute arbitrary code on different events

I've been looking for a simple activator which can execute some code when stuff happens, I haven't found anything yet. Maybe, I am not using the right keywords. It would be great if someone pointed me ...
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3answers
5k views

Are multiple @daily crontab entries processed in order, serially?

I want two jobs to run sometime every day, serially, in exactly the order I specify. Will this crontab reliably do what I want? @daily job1 @daily job2 I'm assuming they run one after the other, ...
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3answers
4k views

/etc/crontab what does “test -x” stand for

In my /etc/crontab file I have: # m h dom mon dow user command 17 * * * * root cd / && run-parts --report /etc/cron.hourly 25 6 * * * root test -x /usr/sbin/anacron || ( cd / ...
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2answers
2k views

How to access X display from a cron job when using gdm3? [duplicate]

Possible Duplicate: Open a window on a remote X display (why “Cannot open display”)? I'm trying to run a cron job that needs access to my X session. I know my X session will ...
5
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2answers
367 views

cron every X exact meaning

In cron you can specify */n where n means every n times period, for instance in the first column is minute. */5 means every 5 minutes, but which minutes? 0, 5, 10, ...? What happens if the number ...
4
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1answer
487 views

Using rsync + cron to sync a machine behind a firewall with my dropbox

I have a machine (A) behind a firewall with no access to the Internet, on this machine I can NFS mount directories on another machine (B) which can access internet, and is accessible from Internet, ...
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2answers
2k views

Running Python script via cron with sudo?

Im using Linux Mint. I have written a python script that is designed to not be accessible to the logged in standard user but is still be executed while they are logged in. It is to run and log them ...
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3answers
635 views

Why does Crontab give me an error with my PHP script when running it from the terminal does not?

I'm having some problems with running the Crontab with PHP files. I have this same php scripts running in the Crontab for more than 6 months but some days ago mysteriously they stopped to execute the ...
2
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1answer
1k views

crontab “0/15” minutes + “11-15” hour field: when does that end?

Given a crontab expression like "0 0/15 11-15 ? * MON-FRI", how is that parsed? I am correct in assuming the 11-15 does not mean "between 11 and 15" but "when the hour is 11-15, inclusive" - i.e. ...
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1answer
4k views

How to remove obsoleted logs with logrotate?

I wanted to remove unnecessary logs automatically , like Xorg.log.0 , and other packed *.gz files , i really don't need that on a laptop system. However , i checked man logrotate , but only an entry ...
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1answer
441 views

vixie-cron.x86_64 doesn't seem to execute jobs on crontab

I have installed crontab on CentOS 5.6 x64 via yum install vixie-cron.x86_64 Here is my crontab -e SHELL=/bin/sh 0 0 * * * cat /root/mysql-backup.txt | xargs ...
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2answers
3k views

How to start the cron daemon

I am using RHEL 5.4 I killed the cron daemon accidentally. I wanted to stop a cron task, didn't know how to do it, ended up killing the cron daemon itself. How do I start it again?
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2answers
3k views

How to run a cronjob in my regular environment?

Both the shell and environment variables that cronjobs are run in is completely different from the ones presented to me in gnome-terminal. How can I run a cronjob under the same circumstances as if I ...
2
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1answer
162 views

Need to find a cronjob

I have a problem, some user ,and I'm not sure who, on one of my servers wrote a cronjob that executes every night at midnight. The cronjob creates a sql dump of a database which is then grabbed by ...
0
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1answer
264 views

Is there a way to combine a file with crontab?

I'm trying to create an interface that will show a message on the screen every set time. Cron is an ideal tool for this case only it doesn't read data from a file during it's run (as far as I could ...
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3answers
1k views

Is crontab multithread?

I don't know where I can find more information about crontab, so I ask here. Crontab is it multithread? How does it work?
2
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1answer
4k views

Cron job not executing

I'm trying to use cron for the first time, and I'm stuck. I'm using Ubuntu 10.10, and the following is my /etc/crontab file. The only modification that I've made is appending the last line. I've ...
4
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1answer
898 views

How to use cron + python to regularly adjust screen brightness?

I want to use cron and this script (http://askubuntu.com/questions/23593/use-webcam-to-sense-lighting-condition-and-adjust-screen-brightness): import opencv import opencv.highgui import time import ...
3
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1answer
729 views

Scheduled task on reboot

How can I schedule a task to run on next reboot? I understand that we have tools like cron and at to help with scheduling. But they seem to allow scheduling at a specific time and not on specific ...
0
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3answers
861 views

How to use gnome-session-save from cron?

I am trying to issue the gnome-session-save --kill command via crontab. I used the command sudo crontab -e. In the file is this: PATH=/usr/bin 00 00 * * * gnome-session-save --kill The command does ...
2
votes
1answer
320 views

Cron & Gnu Screen - Trouble with detached screen [duplicate]

Possible Duplicate: sending text input to a detached screen I have a script for my Minecraft server that runs automatically every 15 minutes. The problem is that after a server reboot, ...
10
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6answers
2k views

CronJob every 25 minutes

I want to know whether there is any easier way to run a job every 25 minutes. In cronjob, if you specify the minute parameter as */25, it'll run only on 25th and 50th minute of every hour
2
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1answer
704 views

Check for process already running in webfaction?

I use Django framework on webfaction and have 5 different cron jobs. One of them lasts much longer than others and sometimes gets stuck (30-120 seconds or more). I have already set that cron job to ...
3
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3answers
7k views

linux cron: want to backup a folder

Hello I would like to backup a folder using cron on a centos. The folder c2duo_mms is located in /usr/local/src/djcode/c2duo_mms. I would like it backed ip every 1:00pm on Tuedays to my home folder ...
9
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2answers
2k views

How can I delete all files in a folder that haven't been accessed in a certain amount of time?

I'd like to run a nightly cron job that deletes all the files in a folder that haven't been accessed in a week or more. What is the most efficient way to do this in bash?
2
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1answer
271 views

Can I bypass crontab command by putting the file?

I need to create and put my cron file with cat cronfile1 cronfile2 > cronfile crontab cronfile -u myuser This works for me, but I want to know if I can do directly cat cronfile1 cronfile2 > ...
2
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2answers
2k views

stop parallel processing for a cron triggered process

I have configured my webservers cron jobs to trigger some php script, every 15min, but sometimes the script takes morethan 15 min to complete execution, by the time another process of the same script ...
3
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5answers
1k views

how to ensure a program is always running but without root access?

Currently I need to have a program running all the time, but when the server is rebooted I need to manually run the program. And sometimes I'm not available when that happens. I can't use a normal ...