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

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start xscreensaver from cron@reboot, ubuntu startup, service/deamon?

I need start xscreensaver for ubuntu, and it can be started in ubuntu startup application. my question is: can xscreensaver be started in cron@reboot? can xscreensaver be started in service/deamon? ...
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177 views

run btrfs balance with cron

Since I run today in a problem with a full disk, which turns out is not unbalanced. Which you can fix with btrfs balance. So my question is: Is there any risk by ruining this by a cron job? (in ...
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1answer
47 views

Can someone be so kind as to setup a cronjob for me? [closed]

I've been trying to get cron to execute these two scripts to schedule and post on twitter, tumblr, facebook and linkedin. It worked once and never again. <?php require ...
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1answer
75 views

high precision subsecond cronjob replacement

I am looking for a cron replacement which could run subsecond schedule, is there have any "still alive" project which serve this purpose? Currently running Ubuntu 14
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191 views

crontab not executing my script?

I added this rule to the bottom of my crontab * * * * * /root/test.sh It basically resets iptables so I can fool around. If I mess up I won't be locked out of my box. When I run the script in bash ...
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2answers
149 views

Emulating /etc/cron.d/ on OSX

On most modern unixes, cron supports individual crontab files in /etc/cron.d, in which each task executes as a specified user. These files automatically update the crontab once edited. They allow ...
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1answer
834 views

Send backup by email with crontab

I use this cron job to do a backup of /home/blah/ each day at 01:00 a.m. : 0 1 * * * tar -zcf /home/blah/backup.tgz /home/blah/ In fact I would prefer that an email is sent to me with the .tgz file ...
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170 views

Are there disadvantages/consequences to adding scheduled tasks directly to /etc/crontab instead of using the crontab command? [duplicate]

CentOS 5.x I noticed that someone (presumably another admin) added an entry directly to the bottom of /etc/crontab so it reads like: SHELL=/bin/bash PATH=/sbin:/bin:/usr/sbin:/usr/bin MAILTO=root ...
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571 views

cronjob does not execute when not logged in

SOLVED, see 'useless' answer. I have a cronjob in my crontab. When I specify the job to be executed in 2minutes, I wait, and then I can see files created by the job, I can see the process with ps. ...
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1answer
151 views

How to restart my server automatically using crontab if they went down?

I have a jar file which I am running like this in my Ubuntu 10.10 and then it starts my exhibitor server in the background - nohup java \ -jar ...
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1answer
111 views

Cron job — If computer inactive for x minutes turn wifi off

I would like to have an alias command in my .bashrc that could be ran at startup. That states: If computer is inactive for X minutes then turn off wifi. How would I do that? I am currently using ...
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1answer
51 views

Cron Job Not working [closed]

I have been trying to create a cron job to execute a script located in ~/Documents/script.sh at midnight every night and every 8 hours after that. I have found a lot of material on this but for some ...
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245 views

Crontab does not work properly in Ubuntu

I am learning how to use cron. I wrote some simple code in my crontab # m h dom mon dow command */1 * * * * echo "1 minute"> ~/Document/cronoutput I expected it to print the words every ...
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1answer
725 views

How to execute recurring Bash script at specific times?

How would I set a script to execute on every Tuesday and Thursday at 11:50am? I've been looking at the at command, but I can't conceive how to use it the way I need to from its man page.
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51 views

fault-tolerant crond replacement

I'm looking for a replacement to crond, or possibly an extension of it. The feature that I definitely would want to have is fault-tolerance. E.g. if a job failed to run due to the computer not being ...
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1answer
108 views

CentOS machine keeps “losing” active directory membership

All of our CentOS 6 machines have been joined to our active directory domain. Each of these machines eventually "loses" their domain membership, which breaks authentication for AD users. I created a ...
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1answer
153 views

Crontab permission problem

I have a fc19 host at work. This morning crontab did not work. $ ls -l /usr/bin/crontab ----------. 1 root root 53472 Jun 11 2013 /usr/bin/crontab The permissions -------- means no one has access ...
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6answers
29k views

What does '>/dev/null 2>&1' mean in this article of crontab basics? [duplicate]

I am reading an article about crontab There is something about disabling automatically sending emails. Disable Email By default cron jobs sends an email to the user account executing the ...
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17 views

Shell script to monitor log files going over a certain size [duplicate]

Due to another issue I'm tracking down, one of my app servers occasionally starts generating a large amount of errors and then becomes unresponsive. For now, the simple solution is to restart the ...
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1answer
163 views

What does */13 do in a crontab?

*/n * * * * in a crontab means run every n minutes, if n divides 60 evenly. What happens for other cases, like */13 * * * *?
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73 views

Configure job to expire

I'm learning Linux at the moment and were doing some exercises scheduling jobs with cron and crontab, but I'm wondering if it's possible to limit the amount of times that the scheduled job is ran. ...
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2answers
239 views

Why does this Shell script fail as cron job [closed]

I have the following in a shell script, when I run this script it works but when I put this as a cron job it does not work(nothing happens!). How come? script #!/bin/bash ...
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1answer
115 views

Please help me to debug this notify-send battery alert script

I used crontab -e to define the following: */5 * * * * env DISPLAY=:0 /home/max/.bin/battery-check.sh The contents of the script are: #!/bin/bash ...
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1answer
2k views

Null message body; hope that's ok

I have the following command below as part of a cronjob. When I run the command via cron or at the command line, I get Null message body; hope that's ok. The contents of the email are empty but when ...
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1answer
94 views

How to do version-control repository update in crontab?

I'm trying to automate version-control repository update in crontab. The following script /home/usr/mrbean/bin/update.sh works in interactive Bash command-line: #!/bin/bash ...
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230 views

Configure cron for daily NMon task

I want to configure a cron job for NMon to gather stats during all day, everyday. Leaving a file per day to dump into NMon Analyser. I know the proper command to get a spreadsheet format its ...
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52 views

CRON path problems

I have a Python script that runs from the command line beautifully, but when I try and run it from CRON does strange things. The script generates, then runs an apk script file. The apk script file ...
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358 views

Cron Log File Outputs Nothing

I get no output from my cronjob. The script the job is executing is: <?php require '/opt/bitnami/apps/wordpress/htdocs/wp-load.php'; ...
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250 views

Cron job scheduled to run on specific day-of-week is running on last day of month as well

I have a cron job scheduled to run every Thursday at 6am via the following schedule: 0 6 * * 4 It's been running as expected, but on Tues, September 30th it ran (unexpectedly) and again on ...
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3answers
56 views

Where is this cronjob running?

We have a news server running on a CentOS 6.5 box. It's leafnode, and a cron is set to run every two minutes. We decide to shut it down to troubleshoot other issues, so we comment out the line in ...
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1answer
188 views

To write this Pseudocode with Regex

I am doing a Makefile which I run regularly by Crontab every day at 0230 crontab -e; 30 2 * * * /bin/thePseudocode Python-like Pseudocode directories = ["Cardiology", "Rheumatology", "Surgery"] ...
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1answer
56 views

Cron, crontab -e reads the wrong file

I do a simple: crontab -e In the top of this file, I have: #DO NOT EDIT THIS FILE - edit the master and reinstall. And I see that it has opened up some temporary file under /tmp I am using ...
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2answers
165 views

Cron job not behaving as expected

So I have a python script that pulls down git/svn/p4 repositories and does some writing to a database. I'm simply trying to automate the running of this script and based from what I see in syslog it ...
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570 views

cron will find certain commands on the PATH but not others

Having issues making crontab run certain commands, despite the PATH and SHELL being set correctly. Here is the env of the machine: SHELL=/bin/bash USER=ubuntu MAIL=/var/mail/ubuntu ...
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3answers
4k views

Cron job to check if PHP script is running, if not then run

I am wondering if someone might point me in the right direction. I've got little experience working with the Linux command line and recently due to various factors in work I've been required to gain ...
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1answer
43 views

Need to automate the updating of the crontab file

We have an automated process where a server is built, and after applications/middleware are installed using another automated process, and the crontab needs to be updated for those ...
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246 views

Do spaces matter in a crontab

It's not clear to be from the manpage for crontab. IS extra white space allowed between the fields? e.g., if I have this: 1 7 * * * /scripts/foo 5 17 * * 6 /script/bar 31 6 * * 0 /scripts/bofh is ...
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117 views

Maintain screen session when executing shell script on boot

Solved: I solved this problem by introducing a delay before executing the script: @reboot sleep 60; /root/start_server.sh On Ubuntu 14.04, I have a crontab entry set to run on reboot: @reboot ...
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1answer
64 views

High precision scheduler daemon

I'm looking for a scheduler daemon like cron, but with at least seconds precision so I can use it for a radio automation app. I've heard conflicting rumors about cron's ability to handle seconds. If ...
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1answer
90 views

Why can I not source a file with the default cron installed on a debian wheezy server? [closed]

I use cron for years now. In order to load all my environment variables at once, I define them in a dedicated file (often but not always .bashrc) that I source in the crontab: * * * * * (. ...
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1answer
253 views

How do I do “Hello World” to try using cron

I am using Fedora 20, and want, eventually, to set up automatic backups. I managed a trial run on my previous Fedora 12 installation, but can't get started again. I am using zshell. I thought I would ...
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44 views

Why is there an apt-get script set in my cron.daily, I'm on Fedora 20?

I found this file tonight: /etc/cron.daily/apt.cron #!/bin/sh [ ! -f /var/lock/subsys/apt ] && exit 0 [ -f /etc/sysconfig/apt ] && . /etc/sysconfig/apt [ $CHECK_ONLY == "yes" ] ...
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2answers
584 views

How to make my bash script be able to create an log file for a clamscan running in cron?

I've created an custom clamscan(clamav) in bash and when I run it in my shell everyhing is fine, but if I run it in a cron, it can't create the log file. This are the errors: ...
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2answers
1k views

Cron job to check if PHP script is running

I am having trouble regarding Cron jobs, I've basically got two PHP scripts that I want to keep running continuously on my server. Currently I am using an infinte loop to keep them going but they seem ...
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1answer
677 views

openSuse, not running the cron job

I have created a cron job in the /etc/cron.d/dispatchingEmail_I the permissions of dispatchingEmail_I are the following: -rw-r--r-- 1 root root 84 Sep 11 19:52 dispatchingEmail_I content of ...
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619 views

Unable to install crontab on OpenSuse

I am running the following command as root, on OpenSuse: linux-gn77-PC:/home/harbir/project # crontab -e when the editor opens up I type the following, as I want the command to be run at 2145 hours ...
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2k views

Using nohup to keep a script running indefinitely

I am very new to Linux and I've only been using it to SSH to my web server using Putty. The issue I am having is this: Basically I've got 2 php scripts. One get_tweets.php constantly listens for ...
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1answer
31 views

Incorrect cron for midnight?

I checked the crontab set by the hosting company and they have this: 0 * * * * /usr/bin/php /www/sites/[domain.com]/files/html/shell/indexer.php reindexall Does this cron run constantly or once at ...
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148 views

Execute All Cronjobs in ~/.zshenv Environment

I want to execute all cronjobs in the environment defined in my ~/.zshenv, and I want to redirect STDOUT and STDERR of every cronjob to a single log file. I am on OS X 10.9. What is the cleanest way ...
2
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1answer
106 views

Qt program not invoked by cron

I had a simple Qt program, when running, it shows a simple window with a countdown timer. If you might be interested in the code, please see here. I had crontab line * * * * * ...