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How can I use Cron to run shells scripts at a fixed time?

rated 0 times [ 2] [ 0] / answers: 1 / hits: 5102 / 1 Year ago, thu, april 20, 2023, 12:35:53

I am wanting to learn cron and I searched for some quality tutorials. I found How do I set up a cron job.

My goal is to have a folder on a network that will have sub-folders. Each sub-folder is a particular script that will be executed by the cron. I don't want to overload our system so how can I create the cron the run a shell script after the assigned time and previous script is ran?

Example:

Main Folder

    Sub1 - script1

    Sub2 - script2

    Sub3 - script3



Cron 10:01 - runs script1

Cron 10:02 - runs script2

Cron 10:03 - runs script3

Cron 10:04 - runs script1

Cron 10:05 - runs script2

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answered 1 Year ago ipentainer · Accepted Answer

Idea Outline

Your friend is an old fashioned cron companion at.

at and batch read commands from standard input or a specified file which are to be executed at a later time, using /bin/sh

Combine this with run-parts.

run-parts - run scripts or programs in a directory

The idea is that you write a cron job which starts the scripts in the "sub folders" with the use of run-parts.

If you want to parallelise the execution depending on the system load, you can wrap the execution of each single script with batch.

Example

On my installations I use my own wrapper script batchme. This provides some enhancements for mailing reports and output.

The cron.{daily,weekly,monthly} scripts are wrapped in my crontab this way:

@midnight   root  test -x /usr/sbin/anacron ||  for script in $( run-parts --list  /etc/cron.daily)  ; do batchme --quiet --info "cron-daily ${script}" ${script} ; done



@weekly   root  test -x /usr/sbin/anacron ||  for script in $( run-parts --list  /etc/cron.weekly) ; do batchme --quiet --info "cron-weekly ${script}" ${script} ; done



@monthly        root  test -x /usr/sbin/anacron ||  for script in $( run-parts --list  /etc/cron.monthly); do batchme --quiet --info "cron-monthly ${script}" ${script} ; done