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

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4
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5answers
2k views

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? ...
-1
votes
1answer
43 views

Cron spamming because of renice [closed]

I have a bash script that I execute using cron. The script begins like this: #! /bin/bash DIR=/home/pi/bin/run renice 19 -p $$ ionice -c 3 -p $$ : Now, every time cron runs this script it sends ...
27
votes
1answer
1k views

Why aren't crontabs stored in user home directories?

I'm curious to know: why are crontabs stored in /var rather than in the user's home directories? It makes it a total pain to isolate these files for upgrades but I suspect that there is a logical ...
4
votes
2answers
344 views

why doesn't 0 0 * * 1 root hostname >> /tmp/hostname.txt work as a crontab?

0 0 * * 1 root hostname >> /tmp/hostname.txt The above cron entry should run midnight on monday and create a file in /tmp called hostname.txt with the output of the hostname command. But it is ...
2
votes
1answer
58 views

How do I set cron to run on background?

I am on ubuntu 12.04 and following this tutorial. I want to setup cron to run in the background but I don't have a chckconfig in sbin so I can't run sudo /sbin/chkconfig crond on I am fairly new to ...
1
vote
1answer
131 views

Shell script and crontab to capture file size, name and date in a CSV file and then send via email?

I have a number of zip files in a certain folder. I want to capture file name and the size of the files in a CSV format in day wise and put it in crontab so I can report on a daily basis, and then ...
1
vote
1answer
34 views

Logrotate behaving unexpectedly

Find below the logrotate configuration that I'm using /usr/local/nagios/var/nagios.log { copytruncate daily rotate 7 compress missingok size 100M } And I could notice that ...
3
votes
1answer
68 views

Crontab suspicious activity

I tried using crontab -l from my terminal as root, it showed no crontab for root. So I tried crontab -e, it returns the following no crontab for root - using an empty one 888 and then the ...
2
votes
1answer
32 views

XML command line tool postgres

I have an XML files to read and load into database daily at night (cron) So i planed to do this in a batch. Is there any command line tool to : 1. Create a postgres schema using an XSD file? 2. ...
3
votes
1answer
106 views

Automatically detect when a file has reached a size limit

I would like to send an email when a file reach a certain size limit. The only way I thought of doing this is by doing a cronjob which will check the file size and send the email if the file is ...
0
votes
0answers
88 views

Using gpg-agent to decrypt password in cron job

I have two scripts that both need to decrypt passwords using gpg-agent. Both of them run fine when launched from the terminal. The problem is that when run via cron, they both fail with these ...
0
votes
2answers
324 views

Run a script at startup

I am using Ubuntu 14.04. I wrote a small script named trial. The contents of the script are as follows: #!/bin/sh SHELL=/bin/sh PATH=/bin:/sbin:/usr/bin:/usr/sbin sh -c firefox I copied the ...
1
vote
1answer
70 views

debian7 cron.allow & cron.deny files

Almost 3 weeks that, in my downtime, I try to find out where the files cron.allow & cron.deny are located in debian7 distro. No way, it seems that by default they are not in the system. 'Just' ...
16
votes
4answers
769 views

Path independent shebangs

I have a script that I want to be able to run in two machines. These two machines get copies of the script from the same git repository. The script needs to run with the right interpreter (e.g. zsh). ...
4
votes
1answer
102 views

BASH_ENV and cron jobs

I have several questions related to non-interactive, non-login shells and cron jobs. Q1. I have read that non-interactive, non-login shells only "load" $BASH_ENV. What does this exactly mean? Does ...
0
votes
0answers
44 views

Fetching all Git repositories in the background

I'm thinking about setting up a cronjob for fetching all my repositories every once in a while, to have the current status ready in case I'm offline. Something like the following (wrapped for better ...
2
votes
2answers
393 views

Logrotate doesnt start proftpd triggerd by cronjob

Im currently running of ideas. The proftpd doesn't restart, if logrotate is triggered by the cron task. Logrotate rotates all logfiles stops proftpd but does not start proftpd again. If i force the ...
1
vote
2answers
641 views

set up local mail delivery to user from cron script

A line in my cron.daily script not work as expected. I haven't any special smtp mail server in system, this line rsync -avun --inplace /oneuser/file.xls /otheruser/file.xls| mail -s "$0 $?" ...
1
vote
0answers
55 views

Cron job running but not establishing tunnel

I have a script which establishes a reverse tunnel on an endpoint HostB. It looks like this: cat tun.sh #!/usr/bin/env bash # Test code /usr/bin/ssh -V 1> /home/userA/bin/tun.stdout 2> ...
0
votes
0answers
85 views

filter cron emails through procmail?

I'm using postfix/mutt/procmail on a Linux/Debian and I've some trouble filtering cron emails with procmail, I just want to move them to the cron/ maildir directory, but no lucky till now. I've ...
0
votes
1answer
50 views

How to force crontab to check for changed files

I have a gentoo Linux system in which I am logged in as root. How can I force crontab to read new/changed files in /etc/cron.d immedeately, so that even a new cronjob is executed if even only seconds ...
2
votes
2answers
90 views

crontab exclude specific date only

How can I write a cron that will exclude a specific date. let say : I need to run a crontab 6pm to 9pm in every 30 min on weekends and want to exclude 10th may 2014 only. Is It possible? How can I ...
2
votes
1answer
358 views

Script to check a folder, print the files then delete those files

I am looking for some guidance on creating a script that will check a specific folder, print all documents (if any) and then delete those documents. I would also like to run this script as a cron job. ...
2
votes
1answer
30 views

Conflict between cron.deny and allow who wins?

which one wins in conflict deny or allow? Is the behavior the same for hosts.allow and all the other similar files?
3
votes
3answers
472 views

Bash script to delete a file called index.html recursively

I need a bash script (not sure how to write the actual .sh file) which I could set to be run by cron every minute and that would delete files with the name index.html that are in a specific directory ...
2
votes
1answer
153 views

kill process in script while writing file behavior

in my php script which runs as a cron job, I have foreach($sites as $site) { exec('./wkhtmltoimage-amd64 ' . $site . ' somefile.png'); exec('./zopflipng -y somefile.png somefile.png'); } ...
1
vote
2answers
43 views

cronjob time 13 * * * *

It surely going to sound like a silly question but i wanted to have a confirm about that crontab time 13 * * * * does it really mean to launch at the 13th minute of every hr of every day of every ...
1
vote
0answers
68 views

Incrontab does not execute command

When I use incrontab out of the box, I mean no changes, I get no result, as if the command was not executed. my incron line is : /crrae IN_CREATE,IN_CLOSE_WRITE,IN_MOVED_TO /usr/bin/unix2dos $# the ...
4
votes
2answers
73 views

System Crontab or Root Crontab

System crontab: /etc/crontab Root crontab: sudo crontab -u root -e Which way is preferred? As they all run tasks within administration privilege.
3
votes
2answers
302 views

Automating backups run from a bash script in Linux the right way

I have a bash script I wrote to backup a Moodle installation. It works fine, I've tested the backups, but there's a problem with it; when I do the backups, since I have to use sudo to type the ...
2
votes
1answer
122 views

Executing PHP with CronJobs in CentOS 6.4 not working?

So I've spent around 2-3 hours now and some times researching, I found several of the same responses online but none seem to work! I'm trying to execute a PHP script every minute (as a test), but it ...
-1
votes
1answer
120 views

How to set up a cron entry that runs at 00 and 30 after the hour?

I have a cron entry that runs every 30 minutes - */30 * * * * /home/myuser/myscripts.sh How to set this up such that it runs exactly at 30 minute intervals but also exactly at (for example) 3:00 ...
1
vote
2answers
67 views

Running a cron job from another shell

I would like cron to run a script from a specific shell (Zsh). I thought the following would work: 00 02 * * * exec zsh; /path/to/script.sh but apparently it doesn't, why? This also made me ...
1
vote
0answers
27 views

How to block the user for a certain amount of time

Suppose, I am working in X environment, and I want to have an obligatory periodic rest. Is it possible to setup a root cron job, that will block my user for 5 minutes every 45 minutes? I am using ...
2
votes
1answer
197 views

Why do deleted files continually reappear?

I've been having a strange issue recently, where I would delete files from a location (i.e. Desktop), and then empty the Trash. However, a day or so later (I'm not sure exactly what triggers it), the ...
27
votes
10answers
13k views

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. ...
0
votes
0answers
100 views

why daily cron isn't running on CentOS 6?

I have a daily cronjob set up on CentOS 6 OS which should look after the log rotation job. The file is /etc/cron.daily/logrotate and it's contents are #!/bin/sh /usr/sbin/logrotate ...
1
vote
1answer
195 views

security concern around adding cron user to web application group

I have a permissions issue on my CentOS 5.6 machine with regards to the cron user. On my test/staging environment my cron user (picco-cron) is a member of one group - picco-cron, as below: ...
4
votes
2answers
9k views

How to start a cron job without reboot?

I use a cron job to call offlineimap every 2 minutes: */2 * * * * /usr/bin/offlineimap > ~/Maildir/offlineimap.log 2>&1 I needed to kill the cron job to fix a problem. How can I then ...
3
votes
1answer
367 views

How do I push a Mercurial repository to BitBucket over ssh? [closed]

I created a public key for ssh and registered that key with BitBucket. I then attempted to push: $ hg push ssh://jhayward@bitbucket.org/johncharrell/[project name] pushing to ...
1
vote
1answer
76 views

Why CRONTAB tasks are lost when quit Putty session? [closed]

I logged to remote computer, running under Solaris, using Putty and added some jobs to be run by cron. When I quit console and logged once again all jobs was lost. crontab -l myuser How do I ...
1
vote
1answer
119 views

automate updates with a bash script and cron

I'm trying to automatize the updates of debian system, without making upgrades. Then i'll send an e-mail to me, everytime there is an upgrade available. I've tryied to do it with cron-apt, but i ...
5
votes
0answers
135 views

CRON Permission Denied [closed]

I have a Debian 7. 3 Server with WebMin installed. I configured a cron job to run every minute as root user, so I run the command crontab -l when I'm logged in as root it shows: * * * * * ...
2
votes
4answers
2k views

Crontab not working

I'm trying execute a basic shutdown crontab to run M-F at 10PM. So I did the following: sudo crontab -e Once inside of the crontab I added the following line: 0 22 * * 1-5 shutdown now The job ...
2
votes
1answer
49 views

How could I signal to a cron job to skip runs?

I have a cron job that runs every X mins and that I would like to have a way to "signal" it not to do anything if needed. Is there a standard way for this? The only idea I had is to check some ...
3
votes
2answers
135 views

Does cron know that the instance to be scheduled is already running?

I was wondering if we add a job in the crontab e.g. to run every 5 mins and the job does not actually manage to finish in 5 mins, does the cron daemon know that the previous instance is already ...
1
vote
2answers
421 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 ...
0
votes
1answer
140 views

Getting a Bad Hour Error in crontab

I am getting Bad Hour error for below peice of code in crontab */05 17-05 * * * wget -q -O /dev/null "http://abcd/cron/abcd" Is there any issue with this. I want the cron to run from evening 5 PM ...
0
votes
1answer
107 views

Cron task starts at 5:30 and runs every 5 mins once

I want to run a crontab cron job which start at 5:30 AM and runs every 5 mins. How do i set it up in Linux? I am able to give like below. But how do i make it 5:30 ? */05 5-16 * * *
2
votes
1answer
64 views

Accidentally typed crontab with just the dash

What happens when I type just "crontab -"? The "e" didn't take before I hit Enter. It just moved the cursor to the next line and I had to Ctrl+C to exit, but I'm not sure what it did exactly. I'm on ...