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

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I want to set up a basic cron job that sends an email

I am running OS X 10.7 and I am learning unix commands. I would like to set up a very basic cron job that sends me an email with a certain message. How would I go about this. From what I have read, I ...
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344 views

How to create a cron which finds/kills/clears old puppet runs?

I am a new user of bash/cron, and I was given a task to create a cron which finds/kill/ and clears old puppet runs that were not successfully installed. The more help the better, but I am more or less ...
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870 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 ...
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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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2answers
500 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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2answers
569 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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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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Logging ALL stderr output of crontab to file

For example, I can log stderr of one script in this way: * * * * * run_script.sh > /var/log.txt 2>&1 But I want to log stderr of all scripts in my crontab. I can append > /var/log.txt ...
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How can I execute `date` inside of a cron tab job?

I want to create a log file for a cron script that has the current hour in the log file name. This is the command I tried to use: 0 * * * * echo hello >> ~/cron-logs/hourly/test`date "+%d"`.log ...
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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.
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1answer
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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 ...
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1answer
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Running cron script with lynx fails to work

I'm trying to automate a login process that can only be done through a browser. I am using the lynx browser to script the actions required to do this. Lynx does this by dumping a user's keystrokes ...
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2answers
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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 ...
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2answers
2k views

Sending cron output to email?

I'm trying to send cron output to an email address and am struggling... I'm running the following command: 13 15 * * 1-5 root /path/to/mysql-backup.sh 2>&1 | mail -s "Daily Database Backup ...
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1answer
136 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 ...
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3answers
817 views

Crontab job not emailing on failure

I have a cron job on Debian: 1 * * * * /home/paradroid/bin/myscript.sh >/dev/null There is an installed and configured MTA, and I have received emails when the script has a syntax error, so I ...
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4answers
693 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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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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How can I run a cron command with existing environmental variables?

How can I run a cron command with existing environmental variables? If I am at a shell prompt I can type echo $ORACLE_HOME and get a path. This is one of my environmental variables that gets set in ...
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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 ...
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1answer
695 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 ...
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2answers
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Using rsync in a cronjob when a password is needed

Basically I have a bash script that fetches data from my server to perform a backup. As it is now I have to start that script manually, enter the password, and then wait for it to finish. I would ...
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1answer
2k views

List of modified files of the past 24 hours

Is there a reliable way to have a system that mails me the list of files that were modified in the past 24 hours inside a set of directories? (like /home/*/public_html/* and /home/*/*domains/*)
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1answer
72 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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1answer
3k 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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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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469 views

Crontab not triggered

I have a program written in C with OpenCV. It captures an image from the webcam and saves on the disk with the name given as an argument. I want to trigger it every minute, thus I inserted the ...
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3answers
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/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
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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 ...
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2answers
329 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 ...
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1answer
453 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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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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1answer
931 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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Run script in a non interactive shell?

I have a cron job that is running a script. When I run the script via an interactive shell (ssh'ed to bash) it works fine. When the script runs by itself via cron it fails. My guess is that it is ...
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1answer
3k 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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Correct locking in shell scripts?

Sometimes you have to make sure that only one instance of a shell script is running at the same time. For example a cron job which is executed via crond that does not provide locking on its own (e.g. ...
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1answer
374 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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Can I automate tar's multi-volume-feature?

Ok, so I've just had a read through this page after a way to improve my current backup solution on my Debian server. Tar seems to be offering a quite nice multi-volume feature, although when I try it ...
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2answers
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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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How do I add an entry to my crontab?

I am using crontab for the first time. Want to write a few very simple test cron tasks, and run them. $crontab * * * * * echo "Hi" doesn't produce anything. crontab */1 * * * * echo "hi" says ...
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2answers
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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 ...
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1answer
149 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 ...
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1answer
209 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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5answers
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How can I use cron to display messages on the screen via notify-send

I am toying around with notify-send and cron (on an Arch machine) and I can't figure out a way to combine them: I tried the solution given here and here, but neither worked. How can I use them? ...
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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?
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1answer
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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 ...
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1answer
790 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 ...
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1answer
608 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 ...
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3answers
792 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 ...
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1answer
290 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, ...