Cron job does not run in RHEL - cron

I'm running RHEL and I'm trying to set up a cron job to run a shell script every 5 minutes.
Following the directions here: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/ch-Automating_System_Tasks.html#s2-configuring-cron-jobs
I have service crond start and chkconfig crond on. Then I edited /etc/crontab and added:
*/5 * * * * my-user /path/to/shell.sh
I did a chmod +x shell.sh. And I made sure to add a new line character at the end.
I'm expecting it to run every 5 minutes but it never executes.
What am I doing wrong?

Simply try to add the cronjob entry and check the script is working fine or not by taking the viewable output in the script.
echo "test time - $(date)" > script.sh
chmod +x script.sh
crontab -e
Then enter the cronjob as below,
*/5 * * * * sh /path/to/script.sh > /path/to/log.file
Check if the log is writing correctly. If its fine, better cross check the script that you are trying to execute via cron. Otherwise it will be a cron issue.

Related

Shell Script not executing, added to crontab

Here is my shell script, myscript.sh located in ~/bin
cd ../environment
. env/bin/activate
python3 office.py
The script office.py updates the database. I've tested and works with no issue. I used this command ./myscript.sh
Here is cronjob */5 * * * * cd ~/bin/myscript.sh added to crontab -e
When i check database, no changes. The cronjob isn't running? How do i solve?
You are not running the script but just trying to change directories, which will fail as myscript.sh is not a directory. You need to first cd ~/bin as you are using relative paths in your script and then run the script. Use this line:
*/5 * * * * cd ~/bin && ./myscript.sh
Also you may wanna check the syslog to check for cronjobs.
grep CRON /var/log/syslog
Have a look at this thread for more information on logging cronjobs.

How to update the crontab and check if its running correctly?

I've modified the crontab with:
sudo crontab -e
and added a cron for a script to run every minute so I can test if it works:
1 * * * * /scripts/backup-script.sh > /scripts/backup-script.logs
Afterwards, I tried to restart the cron service to restart the server but the cron doesn't seem to be working, I tried to use:
crontab -l
and it appears to have the old content as if I didnt even modify it. However, going into crontab -e does show the updated content.
To make your script run every minute your cron record must be:
* * * * * /scripts/backup-script.sh > /scripts/backup-script.logs
What you enter will run every 1st minute every hour
And if you add record via crontab command you do not need to touch cron daemon
To see the cron record you add with sudo crontab -e you must check it with command sudo crontab -l. Otherwise you list cron record of different user

If adding a command that repeats every 10 minutes to crontab, when does the first job run?

As part of the setup of a docker container, the following gets injected into crontab:
*/10 * * * * /opt/run.sh >> /opt/run_log.log
According to the behavior of crontab, when should the first run kick off? Should the 10 minute cycle begin instantly, or 10 minutes after this is put into crontab. Neither behavior is happening so I am trying to debug this in more depth by trying to understand the intended behavior.
This cron sandbox simulator gives you an idea:
Mins Hrs Day Mth DoW
*/10 * * * *
This run time (UTC) Sat 2016-Jan-23 0653
Forward Schedule Sat 2016-Jan-23 0700
Sat 2016-Jan-23 0710
Sat 2016-Jan-23 0720
It uses the syntax:
Every nth '0-23/n', '*/2' would be every other.
'*/1' is generally acceptable elsewhere, but is flagged here as possibly an unintended entry.
See for example "Run a cron job with Docker" (by Julien Boulay)
Let’s create a new file called “crontab” to describe our job.
* * * * * root echo "Hello world" >> /var/log/cron.log 2>&1
# An empty line is required at the end of this file for a valid cron file.
The following DockerFile describes all the steps to build your image
FROM ubuntu:latest
MAINTAINER docker#ekito.fr
# Add crontab file in the cron directory
ADD crontab /etc/cron.d/hello-cron
# Give execution rights on the cron job
RUN chmod 0644 /etc/cron.d/hello-cron
# Create the log file to be able to run tail
RUN touch /var/log/cron.log
# Run the command on container startup
CMD cron && tail -f /var/log/cron.log
Then you can build the image with
sudo docker build --rm -t ekito/cron-example .
And run it:
sudo docker run -t -i ekito/cron-example
Be patient, wait for 2 minutes and your commandline should display:
Hello world
Hello world
If you replaced the first '' by '/10', you would have to wait to the next 0 or 10 or 20 or... of the hour.

Shell script cronjob

I need a shell script that would run two .sh files which are in the directory: /opt/tomcat-latest/bin
#!/bin/sh
cd /opt/tomcat-latest/bin
./shutdown.sh
./startup.sh
Would this code achieve my goal? If so how do I make it on a cron job that runs every 2 hours? I have a Linux Centos VPS and DirectAdmin admin panel.
I think the easiest solution would be to run directly the commands with its full path from cron, instead of using a sh script.
Something like this in the crontab would work :
* */2 * * * /opt/tomcat-latest/bin/shutdown.sh && /opt/tomcat-latest/bin/startup.sh
That would run every 2 hours
you can edit crontab with crontab -e and check the crontab syntax here : https://fr.wikipedia.org/wiki/Crontab

Downloading files with bash via cron

I have build a bash script that gets .tar.gz files from IMDb and writes to a log file, the script works when run on its own as I can see the folder with the files present, but when I run the script via cron it doesn't work. Would this be due to permissions? I have edited the sudo crontab file, but I'm not sure what else I need to do.
Try this solution:
Cronjob is a file that contains your job:
cat cronjob
* * * * * bash /path/to/script.sh >> /path/to/log.txt
Then you should set executable permission and start cron service:
chmod +x cronjob
/etc/init.d/crond start #redhat based servers like centos
/etc/init.d/cron start #debian based servers like ubuntu
After that you should tell cron service to run cronjob file:
crontab cronjob
Your script should download a file.
If your script doesn't run you should run it from good path[full path], so your cronjob file would be something like this:
* * * * * /bin/bash /path/to/script.sh >> /path/to/log.txt

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