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

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Running smsd gnokii on boot

I can successfully run smsd but I could not run it on boot. I tried using rc.local and @reboot cronjob but none of the two worked. Does anyone tried to successfully run the script on boot?
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1answer
35k views

Where to find the Crontab logs in CentOS

First of all I'm using CentOS [root@a etc]# cat system-release CentOS release 6.5 (Final) [root@a cron.daily]# ps -ef | grep cron root 982 1 0 Jun14 ? 00:01:15 crond root ...
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78 views

Strange cron behaviour

I have a script that reads a list of IPs from a file, compares with the existing ones in a chain, and adds recently added IPs in the file into that chain. Running the script manually (e.g., ./script) ...
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59 views

Can I change the exclude file list while running rsync under a cron job

I am using Fedora 20, MATE desktop, zshell. I have started a cronjob to run, every evening, an incremental backup using rsync, closely following the suggestions here. After the first run yesterday, ...
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1answer
65 views

Switching shells for one cron job

Say I have the following in my crontab: * * * * * command1 -option A; command2; command3; etc. I would like cron to run the commands I have in that line with a specific shell. How can I do that? ...
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1answer
209 views

Get chronological list of dates & times for scheduled tasks in cron

Given a job specification in crontab, is there any way to get the list of dates and times the job in cron will run in the next week? For example, given a string 10 13 * * *, is there any way to get ...
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1answer
325 views

Where is NMon cron job for AIX?

While trying to know where is NMon job configured to run; I do find that it's NOT listed on Crontab (using crontab -l). BUT - the job is currently running as expected, which is weird. See the ...
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2answers
243 views

bash script cronjob not working

Why is the cronjob below not working? As manually executed script is working, but if I put it on cron job it doesn't push through. #--------Reports------------- 25 11 * * * /logs/scripts/chim/...
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713 views

Issue running Python script via cron inside Docker

I have an official Ubuntu 14.04.1 container running via Docker. cron is working fine, I added * * * * * /bin/echo "working" >> /test to my crontab using crontab -e and then I started cron with ...
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102 views

How do I suppress all email notification from cron for particular job?

I am scheduling the following shell script #!/bin/bash (echo open mailserver.nowhere.local 25; sleep 1; echo EHLO; echo quit)\ | telnet | grep "?Invalid command" if [ $? -eq 1 ]; then ...
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88 views

SASL authentication fails when called from crontab

When I run mbsync from the command line it works fine. But if mbsync is run from the crontab, mbsync fails with this error "Error: SASL(-1): generic failure:". My guess is that mbsync's SASL ...
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1k views

Cron several script every 5 minutes with 10 second between each script

I have several file setup in my crontab, all those scripts must run every 5 minutes. The problem comes when those script need to much CPU and IO at a time and the machine become unavailable. To ...
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104 views

Logrotate or scripting to manipulate log file

I want to make sure that a certain log file gets empty when it reaches a specific size. I first used logrotate since the man page says: It will not modify a log multiple times in one day unless ...
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1answer
131 views

In crontab, @reboot is working but regular not working

I am studying linux on my raspberry pi that installed debian version. There were no problem, worked perfectly in crontab, but something has occured. @reboot sudo bash /home/pi/IP_check.sh */10 9-...
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1answer
93 views

How to suspend a process for a certain period of time?

I have several running processes which is started by a shell, but I don't want them to run during 08:00am - 20:00pm for each day because they are really bandwidth-consuming, so , I have to suspend ...
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1answer
44 views

Killing a process with cron as soon as it starts

I want to stop dropbox from running as soon as I log into my account. Now I know I could do this simply by going to Startup Applications and disabling dropbox. But I was wondering if there is a cron-...
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195 views

How to monitor the integrity of a script that is running?

I want to make sure a running python script was not modified accidentally by some other process (or cosmic ray, or unexpected developer update). I've heard of comparing a checksum of the script (e.g. ...
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2answers
115 views

Changing user's wallpaper via system crontab

I tried to set up wallpaper change via cron in /etc/crontab, but I failed. DISPLAY env set directly / before cmd, but still it's not working: DISPLAY=:0.0 * * * * * ad env DISPLAY=:0.0 /usr/bin/...
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98 views

How to set one job to run at precise time with anacron without losing config at next upgrade?

I want logrotate to run at a precise time daily. Currently it is set to run at some random time using anacron and I don't want to change the randomness factor for all the other jobs. I have ...
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82 views

How to know the which jobs are scheduled in cron for today

I am looking to get the details of jobs which are scheduled to run from cron for today and need to make it as a script by 12AM every day to get the job details that are scheduled for today and like ...
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2answers
293 views

change the name for root mails from cron

I have two servers that are synchronized with rsync, one is the failover server of the other, so they both have the same name. Now root mails that are sent to my other account are all named from root ...
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1answer
26k views

How to run a cron job to execute every minute?

I am trying to create a directory having timestamp in its in name in the /home directory. I have created the following cron job as root user. But it's not running. What am I doing wrong? Following is ...
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211 views

Shell script runs differently when schedulled with cron

I have a strange problem with my backup script. To begin with, this is the backup script: ########################################################### # CODE BEGINS HERE #############################...
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1answer
123 views

Remove tar compress spool from cron email

I have a crontab job that call a simple script to backup a website: 15 0 1,10,20 * * /home/username/bin/backup_whatever This is the script: #!/bin/bash TODAY=$(date +"%Y%m%d") FILE_TO_PUT="...
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72 views

Edited /etc/cron.d/anacron, changes are immediately in effect?

After editing /etc/cron.d/anacron and saving the file, are the changes immediately acknowledged by cron? Or do I need to run a command to tell cron to reload /etc/cron.d/anacron?
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168 views

Scope of shopt options in cron script

I have a bash script that is run nightly in a cron job. It needs to do case insensitive file matching, so the script calls shopt -s nocaseglob I want to make sure this does not affect other cron ...
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1answer
546 views

Cron can't access my home directory when I'm logged out

I have quite a strange problem using cron. I distilled it thus far: I created following simple bash script in /home/user1/cron_dir/cron.sh: #!/bin/bash echo "Success" As user1 I created following ...
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41 views

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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1answer
345 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
53 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 '/opt/bitnami/apps/...
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1answer
139 views

high precision subsecond cronjob replacement [duplicate]

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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423 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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348 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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2answers
3k 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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480 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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2k 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
328 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 /pekooz/exhibitor-1.5.1/lib/exhibitor-1.5.1-jar-with-...
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1answer
152 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
71 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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404 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
3k 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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1answer
59 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
230 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
578 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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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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1answer
454 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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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
442 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 file="/home/nalangi/...
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1answer
209 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
4k 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 ...