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

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2
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178 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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1answer
21 views

Rolling job scheduler

I have a number of servers that I want to perform the same jobs on, one server per day, once the final server has been acted upon the script should return to server1 and start over again. The jobs ...
4
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1answer
114 views

How do I schedule a cron task to run

I'm looking to crontab a script every hour starting Friday at 5pm... ending Monday at 5am. This script checks if it's completed this week and if it's currently running. If no/no, start task. Off the ...
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1answer
37 views

Use of Verbose in a cron job

I'm busy setting up a back-up script to run on my Pi using rsync. I see that a number of people use the -v option in their cron jobs. Why? It's going to be run as root, and not in a terminal where ...
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2answers
3k 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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1answer
38 views

How can I set the MAILTO variable for an at job on AIX? [closed]

I'm calling at jobs on AIX servers using this method: /usr/bin/at now +1 minute << EOF chmod 700 /var/tmp/somescript.sh cd /var/tmp sh /var/tmp/somescript.sh > 2>&1 EOF If ever some ...
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1answer
44 views

Using 606 file permissions in /etc/cron.d. (root) BAD FILE MODE)

I have a file in /etc/cron.d with 606 permissions to be run by root. The intention is to provide read & write access to 'others' via 606 to allow a script to modify the file. Cron does not ...
1
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1answer
41 views

sh script containing perl element does not produce same output via crontab as manual execution

I tried posting this on Stackexchange but I think I may have more chance of a correct answer here as its very linux specific. I have an sh script which updates data in a csv, then runs a perl script (...
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0answers
530 views

How to stop mail with PHP error messages to root?

Today, my Centos has a problem. When I type df -h in SSH I get: /dev/vzfs 61G 61G 0.3G 99% / The disk is full. I found that /var/spool/mail/root is nearly 53GB. tail /var/spool/mail/root -n 50 ...
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0answers
22 views

Settings of Poller Interval and Cron Interval on cacti

Latest version running of Cacti on linux machine and I am bit confused with Poller Type, Poller Interval and Cron Interval. The current setup is set to monitor ping latency, linux machine and dns ...
1
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2answers
27 views

@reboot jobs don't work

I have been trying to make my fedora pc do a little script at reboot but i can't get it to work. My script works perfectly, for example if it's 02:10 and inside crontab -e I write 11 02 * * * /path/to/...
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1answer
39 views

why the executing shell within cron job will take longer time than normal? [duplicate]

I have a shell script which will run project consist of multiple JUnit tests. Then I call this shell within cron job every a period of time. In this case, I observe the following: Time to complete ...
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2answers
33 views

crontab each 12 hour - when will it send an email?

I am installing new crontab job which will execute a shell script and then send the printed errors on the console to email. I know all of the required steps to do, which will be as following: 0 10,...
0
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2answers
77 views

How to run multiple scripts at a same time?

Suppose I want to run five different scripts at 3 PM on every Saturday and I want to put all these scripts in a single script and run it using cron.
1
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1answer
27 views

when the cron job start after installing new crontab?

I need to a crontab execute each 12 hours, so I have the following: 0 */12 * * * . /X.sh then Linux is installing new crontab. after that, I am waiting for 2 hours and still the cron job didn't ...
1
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1answer
55 views

How to schedule run shell script that opens Firefox [duplicate]

I have the shell script which opens Firefox and launches macros in it (I use a Firefox add-on called Imacros to create macros). The content of my shell script named house.sh is like that: firefox ...
0
votes
2answers
1k views

Pushing to a Git repo from shell script

I'm trying to commit/push changes to a remote Git server with the below sample code: #!/bin/sh USER='username' REPO='/home/'${USER}'/Sites/git/bitbucket/kb' COMMIT_TIMESTAMP=`date +'%Y-%m-%d %H:%M:%...
1
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1answer
52 views

Running a cron job randomly for every one hour

I want a cronjob to run every one hour randomly. (i.e if the first job runs at 58 minutes,the second job should run at 47 minutes and the third one at 52 minutes and so on) But this should run ...
1
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1answer
31 views

My backup_system.sh file didn't run under crontab

So i created a script used to backup system, i tested and it worked. Here's the script: #!/bin/bash backup_files="/home /var/spool/mail /etc /root /boot /opt" dest="/mnt/backup" day=$(date +%F) ...
1
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0answers
22 views

Minecraft acting differently when started from terminal compared to started by cron job at start-up

So I use a CentOS Linux 7.2.1511 server, where I host a couple of things, amongst them a Minecraft server. Since from time to time server is rebooted I scheduled a cron job to run minecraft server on ...
1
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2answers
22 views

Get owner / user of a cronjob

In Linux (Mint / Ubuntu), I can create cronjobs for each user individually. Is there any way, I can find out the name of the user against whome the cronjob is running. I want to get the username of ...
1
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1answer
36 views

Get a list of all scripts and their paths which are run as cron job

I am looking for some script or terminal command to list all the scripts (preferably with their paths) which are run on a periodic basis by cron, cron.daily. I am not looking for any filter for time-...
1
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1answer
59 views

launch process foreground on boot

I know how to launch programs in the background with cron on boot or at certain intervals, but in this case, I want to launch a python script in the foreground, automatically when the computer starts, ...
1
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1answer
35 views

Crontab and NMCLI

I have created a script called connection.sh, it is used to automatically connect to my vpn : #!/bin/bash nmcli connection up MyVPN I have already tested it, and it works if I launch it manually, ...
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2answers
52 views

Where are my lost cron jobs?

I am trying to port the code over to a new server hosted somewhere else, and I want to know what cron jobs are running on the old box. Where can I find these? crontab -l SHELL="/bin/bash" 0 0,6 * * ...
0
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1answer
45 views

Custom scripts under /etc/profile.d and /etc/init.d - rhel6 and rhel7

I need to start my script during boot time. I have read that the scripts under /etc/init.d & /etc/profile.d are sourced during system startup. How different are these directories? Other than the ...
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3answers
12k views

crontab error with (No MTA installed) but I use >/dev/null 2>&1

I'm new on linux user I try to run crontab to backup my database with vagrant user * * * * * /usr/bin/mysqldump -h localhost -u root -p root mydb | gzip > /var/backup/all/database_`date +%Y-%m-%...
5
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2answers
23k views

What are the runtime permissions of a cron job?

When a cron job runs with what privilege does it execute? I'm not sure about that. Is it with the same privileges of the user that added it via crontab -e?
8
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3answers
6k views

Crontab entry with hour range going over midnight

Is this valid crontab time specification, doing what is expected: 0 22-4 * * * Or is it necessary to do something like 0 22,23,0,1,2,3,4 * * *
0
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2answers
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 ...
0
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2answers
39 views

Does cron execute jobs asynchronously?

If I add 5 jobs in my crontab, do they execute asynchronously in parallel ? Two of my jobs may take 10 minutes to complete and I want to know if I need to run them in the background (by adding the &...
0
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4answers
74 views

Ensure that cron daemon stays running

If on a debian 7 server (wheezy) running in a hosted VM and an up-to-date cron daemon there is a bug so cron stopped running without obvious reason. Since this only happened once ever since, it is ...
0
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1answer
20 views

cross-reboot monotonic systemd timer

The timer functionality of systemd includes monotonic timers, which measure time in real uptime since some starting point after boot. This means that after a boot, the service triggered by the timer ...
1
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1answer
61 views

Two cronjobs not working (one to start a process, one to stop a process)

I typed the following into crontab -e 0 0 * * * bitcoind -datadir=/home/pi/bitcoinData -daemon 0 6 * * * bitcoin-cli -datadir=/home/pi/bitcoinData stop I expect this to run bitcoind -datadir=/home/...
11
votes
8answers
6k views

cron Vs. sleep - which is the better one in terms of efficient cpu/memory utilization?

The Case: I need to run some commands/script at certain intervals of time and for this I have two options: set up a cron-job implement a loop with sleep in the script itself. Question: Which is ...
5
votes
5answers
2k views

nginx logrotate error on cron job

I'm running Ubuntu 14.04 LTS and nginx on a Digital Ocean VPS and occasionally receive these emails about a failed cron job: Subject Cron test -x /usr/sbin/anacron || ( cd / && run-parts ...
0
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2answers
57 views

Cron Job: Redirecting shell script output to a file

Just an one line shell script below not working as a cron job but executing directly from terminal works fine: #!/bin/bash echo "Executed" >> ./crond.log 2>&1 What might be the ...
2
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1answer
803 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 ...
0
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1answer
62 views

How to run a script outside of home directory via cron

I have a script located at /home/user/backup.sh I'm trying to execute this script via my root crontab. It isn't running. The script works if I create the crontab under my user account. Is there ...
0
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0answers
43 views

Default crontab that executes cron.(hourly|daily|weekly|monthly)

I have to build a crontab that will execute (with run-parts) any script located in the standard /etc/cron.(hourly|daily|weekly|monthly) folders. I have never done this before. Does this look correct?...
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votes
1answer
77 views

Shell script to delete logs when the disk space reaches 90%

I need help to develop a shell script to delete the logs automatically once the disk space reaches 90%. I can add this shell script to crontab jobs.
1
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3answers
122 views

add text on line before match

Trying to add text on the line before that it find the match (updateKey.sh) in this case, but won't get it to work. Here is my crontab file that the script adds the line to 0 06,18 * * * /home/server/...
48
votes
11answers
35k 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. ...
-2
votes
2answers
59 views

Why does running a Cron Job as root stop the sshd service and disallows login for other users?

I have a script for getting Clamav updates from another server which I run as a Cron job as root. Also, I have root login disabled for /sbin/nologin. But this has serious implications on the system as ...
6
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5answers
2k views

Change the time zone of a cronjob

I have a cronjob which is executes every day at 9:00 AM of UTC-Time. I'm in GMT+1 so it executes at 10:00 AM local time. When there is the timezone change (to daylight saving time, DST), the cronjob ...
13
votes
1answer
500 views

Cron vs systemd timers

[NOTE: The intent of this question is to help people evaluate whether systemd timers would be a good choice for their job timing needs. Many (most?) people are probably using cron, but maybe some are ...
0
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1answer
112 views

CRON: pam_unix(cron:session): session opened for user root by (uid=0): Is it a must have process?

This post is somewhat similar but mine is rather specific. CRON: pam_unix(cron:session): session opened for user root by (uid=0) Is this really a bug? In our system this process is creating ...
0
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0answers
24 views

cron job quit working after latest apt-get upgrade

I've been running a cron job every 15 minutes for years, with few problems. Sometime in the last week, it quit running, I'm assuming after a apt-get upgrade && apt-get dist-upgrade. I was ...
13
votes
7answers
26k views

How to restart the Python script automatically if it is killed or dies

I am running my Python script in the background in my Ubuntu machine (12.04) like this - nohup python testing.py > test.out & Now, it might be possible that at some stage my above Python ...
3
votes
1answer
43 views

Why am I seeing much more cron jobs in webmin than in `crontab -e`?

I am just starting to learn cron jobs. Basically I am going to use webmin to manage my cron jobs, I am also reading some basic information about cron jobs. So far I've learned that /etc/crontab ...