Questions tagged [cron]
Cron is a job scheduler that allows users to run commands periodically.
2,318
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How do I declare and use a variable in crontab that will hold the name of the admin user account?
I want the crontab for root to be agnostic, i.e. I don't want to literraly specify in it that the admin user is jim. That is why in my crontab for root I introduced the variable au.
SHELL=/bin/bash
...
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1
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shell .sh script does not execute all tasks within, except when run manually [duplicate]
I run a shell script at reboot, by having it in my crontab:
@daily apt-get update && apt-get upgrade -y
@reboot bash /root/Start.sh
@reboot /bin/bash -c 'sleep 10 && /bin/mount -a'
...
...
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1
answer
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Trying to periodically backup /var/log while using journald
I'm trying to periodically backup my /var/log directory, but journald manages the logging on my system. Is the correct way to just tar -cf log.tar /var/log?
The way journald saves it's log files in /...
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Anacron doesn't appear to run anything on Debian, but why? [duplicate]
I have an odd problem with my Debian server. Up until a few weeks ago, anacron was running my cron jobs fine and I can see I have backups from then so it was running stuff. Then it appears to have ...
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Allow cronjob to restart systemclt user unit
I have a systemctl user unit:
[Unit]
Description=my app
Wants=network.target
After=syslog.target network-online.target
[Service]
Type=exec
ExecStart=/home/user/bin/myapp
StandardOutput=append:/home/...
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35
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Systemctl Suspend Inside Cronjob
I have a cron:
* * * * * /usr/local/bin/script 2>/tmp/cron.log
And the script:
#!/bin/bash
if <some validation>; then
systemctl suspend
fi
So I get the error when cron executed:
Call to ...
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1
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58
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What is the meaning of a trailing hyphen in this crontab command? [duplicate]
I was looking into how to programmatically add a cronjob, and came across this SO question which advises using the following one liner:
(crontab -l 2>/dev/null; echo "*/5 * * * * /path/to/job -...
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How to automatically start mate-terminal the CLI way on every system start?
UPDATE - replies to the comment section - base posting after that:
I really wanna do it the CLI way - reducing my GUI dependence as a user. So, you think I'd better head into the direction of ...
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53
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rsync cronjob succeeds during the day but always fails to find the destination at night. Might my external hard-drive "go to sleep"?
NOTE: there is an easy solution to this problem (i.e., just backup your data during the day!), so this is not an urgent problem. But I have searched extensively on stack exchange and askubuntu and ...
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1
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crond not sending mail to non-root user
RHEL8 system here. Outputs from /etc/cron.daily... produce the expected email output, but my user's own crontab doesn't. Here's a test that sums up my problem:
~$ crontab -l
MAILTO=dh
* * * * * ...
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0
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43
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anacron not running weekly scripts
/etc/anacrontab:
# /etc/anacrontab: configuration file for anacron
# See anacron(8) and anacrontab(5) for details.
SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
...
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1
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34
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CLASSPATH in crontab
I am having trouble getting my Java program to run from cron. I am able to recreate the problem, using a simple example, as explained below:
In the file /path/to/javaenv.txt I define my CLASSPATH ...
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4
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140
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Cron Job: Best Practices
I have written a bash script which will be setup as a cron job in the future.
During the script development I have added echo lines to help me follow and debug my code, like the code snippet below:
#!/...
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1
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82
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using a cron job to automatically backup the same drive using dd
so I want to backup my system drive (full drive not just partition) every month using dd, in an external hard drive. So I have something like this in my crontab
0 9 1 * * dd if=/dev/sda | gzip -c &...
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41
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Date format in /var/log/cron (Oracle Linux Server 8.8)
Currently the date format in /var/log/cron seems to be %b %d %H:%M:%S, so in /var/log/cron I see the logs like
Aug 20 03:13:01 bhost1 CROND[1361808]: (user1) CMD (......)
Is it possible to change the ...
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2
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1
answer
334
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When you alter permissions of files in /etc/cron.d in Ubuntu, do they persist across updates?
It seems like an no brainer question, but i did not manage to any real information. In my Ubuntu server i have created a custom /etc/cron.d config file, e.g. /etc/cron.d/MyCronTab, the reason I put ...
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1
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72
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Cron execution not normal
When I run job.sh in terminal, it works. In there there's just following:
#!/bin/bash
cd /home/user
node script.js > file
When I run it from CRON, it just creates file and no text is there, if I ...
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1
answer
106
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Is there a tool to test if a date-time is in a given range?
I need to develop a script to test if "now" (e.g. the output of date) is in a given range. For now, this range is expected to be a list of days of month (e.g. 10,11,12,13,21,22,23). And I ...
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53
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cronjob: run script_A on boot/wake, then every 5 mins after that, run script_B on each of the 4 mins in between (so *not* just modulo-5 clock-minutes)
So I'd like to set up a cronjob in a very specific way:
run script_A on boot/wake
then every 5 minutes after, relative to that boot/wake (so not just modulo-5 clock-minutes)
run script_B on each of ...
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1
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29
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`cronnext` reports `nextstring` for every-minute cronjob as beginning of the *current* minute, ie in the *past*. Normal?
So I'm seeing this weird thing (or at least, weird to me, with my tiny amount of experience).
cronnext tells me the nextstring for an every-minute cronjob is the beginning of the current minute,
ie ...
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0
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187
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How to update google-chrome on centos with yum-cron?
I'm managing a medium size Selenium grid based on Linux CentOS 7 - a total of a couple dozens linux VMs. I'm using yum-cron to install updates. Starting recently, google-chrome does not update ...
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2
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66
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Turn on keyboard backlight from multi-user.target
Is there a way to turn on the keyboard backlight from the multi-user.target environment? As X11 is not loaded, the command xset led on does not work and gives xset: unable to open display ""....
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0
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53
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xfconf-query not working when called from cron / how to run UI dependent programs per cron?
When running
/usr/bin/xfconf-query -v -c xfce4-desktop \
-p /backdrop/screen0/monitorHDMI-1/workspace0/last-image \
-s $HOME/Photos/somephoto.jpg
on the command line, it sets the background image ...
- 888
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0
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144
views
Why is my systemd-timer not working? (Active = Until)
I created a systemd-timer which should restart a docker container daily but it never does.
That uptime of the docker container is > 1 day, that shows me the container was not restarted
/lib/systemd/...
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1
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33
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Accessing interactive output of command started in crontab
I'm running a game server (Minecraft) on Raspberry Pi OS. I want the server to start whenever the device starts so I've added the following line to crontab:
@reboot user cd /home/user/nukkit &&...
13
votes
1
answer
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When a file path longer than 100 characters is passed, crontab throws an error saying "No such file or directory"
$ touch aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaBBB
$ crontab ...
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votes
6
answers
840
views
Update crontab rules without overwriting or duplicating
I'm trying to figure out a good solution to the following problem:
crontab contains some default rules (A,B,C)
I have a setup.sh script that should append rules from a file my.cron to crontab (...
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-1
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2
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170
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Why are comments in the same crontab line as the crontab job are not allowed?
It might depend on my none native English but the crontab.5 manpage contradicts itself.
Blank lines and leading spaces and tabs are ignored. Lines whose first
non-space character is a pound-sign (#) ...
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41
views
Crontab job with grep and ls -ltr [duplicate]
I am trying to schedule a job using crontab, but it is not giving any output. The same thing I am able to do through a script, and is solving my problem. But I would like to know what mistake I am ...
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27
views
How can I use crontab to delete a specific folder name [duplicate]
I've created some folders with a year-month stamp on them (ex: 2023-03). I've tried creating a crontab script to delete folders older than 2 months. In the directory I would have folders like 2023-03 ...
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79
views
Crontab jobs during suspend will not run?
Environment: Linux XUBUNTU 22.04.2 LTS on an ACER ASPIRE laptop.
Tools: Using Linux Text Editor to create a bash script also tried
using crontab to execute each command a minute apart.
Goal: To have ...
0
votes
1
answer
50
views
mandb generates all possible languages in /var/cache/man
In Debian 12, the following command is run weekly:
start-stop-daemon --start --pidfile /dev/null --startas /usr/bin/mandb --oknodo --chuid man -- --quiet
which generates man caches in /var/cache/man
...
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1
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95
views
Using '/usr/bin/cd' in a cron script fails while 'cd' works
I have a simple shell script that I am running via cron. I am using it to perform a scheduled git pull operation (yeah, I know there are probably better methods, but this is another team's repository ...
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2
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112
views
save the output to multiple files in crontab
There is a script scheduled in crontab.
0 2 * * * /usr/local/bin/backup.sh >> /root/output_all.txt
I want to save the output into multiple files like output_all.txt and output_date.txt at the ...
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1
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122
views
Schedule a cron task to be repeated every day?
All the google results mention cron jobs. They don't work, I followed multiple guides exactly, and the script is never launched.
I just need to set the brightness to change at morning and dusk, it ...
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0
answers
125
views
My Crontab doesn't work on Raspberry Pi
I have a python script in:
/home/pi/auto/wake_up.py
crontab -e:
* * * * * /usr/bin/python /home/pi/auto/wake_up.py >> /tmp/wake_up.log
log is created but with empty line
same when I put
#!/usr/...
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1
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188
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What things can be done to make a Bash script containing sudo commands, running with the timer schedule ‘crontab’ work?
I try to run a script that I named script1.sh:
out="/home/me/scripts/out.txt"
sudo ntpdate 99.99.99.99 >> $out
on a timer with the crontab in a Centos 7 operation system. The aim of ...
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1
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82
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Cron works at 5pm instead of 5am
I have this /etc/cron.d/reboot file:
PROJECT_ROOT=/usr/local/share/applications/ana
NODE_PATH=/usr/bin/node
REBOOT_SCRIPT=/usr/sbin/reboot
SCRIPT=scripts/server-reload-messages.js
0 5 * * * root cd $...
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33
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solaris 10 code below works fine, but is nothing is ever generated via cron
root crontab
20 * * * * [ "$(ls -A /var/spool/lp/requests/localhost/)" ] && echo "lp queue not empty " || echo "lp queue empty" | /usr/ucb/mail [email protected] ...
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0
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1
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132
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Fixing a cronjob issue when running a script and cron task being deactivated [duplicate]
I am running OpenSUSE 15.4 and I am trying to set up a CRON job using crontab -e.
Inside my CRON tab I have the following:
*/1 * * * * /usr/bin/Rscript /run/media/matt/A34E-C6B8/folder/myRScript.R
So ...
3
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1
answer
203
views
What effect has "+:ALL:cron crond" in /etc/security/access.conf?
I am refining our rules in /etc/securiy/access.conf. I found the following rule and I am not sure what it is used for:
+:ALL:cron crond
According to the man page of access.conf it means something ...
2
votes
2
answers
998
views
Schedule a job every 20 days [duplicate]
I want to know whether there is any easier way to run a job every 20 days. In cron job, if you specify the day parameter as */20, it'll run only on 20th day of each month, IE basically becomes once ...
- 1,354
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182
views
How to make Linux reboot every 30 days even if the clock gets corrupted
I'm running a headless networkless raspberry pi zero to control some hardware**, and occasionally the time/date gets corrupted, maybe other things too. While it's not a perfect fix, rebooting the ...
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1k
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Cron Job vs. Scheduler: Understanding the Differences and Use Cases
What are the key differences between a Cron job and a scheduler, and in what use cases is using one of these tools more appropriate than using the other?
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89
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Allow a certain set of domain names corrisponding ip with resolution and whitelisting on the fly
I'm trying to setup a firewall config for a specific machine. The firewall is configured to block all traffic except for a certain set of allowed IPs.
Today I was asked to put on a teamviewer service ...
- 2,816
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votes
2
answers
741
views
Run shell script file once after reboot
I am stucked on how to execute a shell script only once after the machine reboots, the file that I have has the following content where I am writing a test to get only the first element from the file:
...
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0
answers
82
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Cron doesn't run the Cron Job I wrote [duplicate]
I wrote a Cron Job and it doesn't run. Any Idea why it doesn't run?
This is the Cron Job I expect to run:
#
#
# (day of month) (day of week)
# min hou dom (day ...
- 249
3
votes
0
answers
160
views
A monotonic systemd timer that is not distorted by suspension and downtime?
This is what I want: A timer that runs every X minutes by the wall clock. If the computer is asleep, then it should run as soon as it wakes up. And then again and again, every X minutes by the wall ...
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0
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211
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SSH/Cron services hangs on RHEL 8.6
So, i have an odd issue with my VM RHEL 8.6 test server with Hyper-V.
The problem is the SSH Service hangs from time to time, around midnight.
To connect again to the server i have to Reboot it ...
- 101
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0
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142
views
Using systemd timers every hour with multiple commands
First time user trying to switch from cron to systemd timers.
Currently I have a crontab with the following line:
10 * * * * cd /some/where; export ENV_VAR=...; ./executable with params
Is such cron's ...
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