I use cron mainly for backups, though you can also use it to run all sorts of jobs on a schedule. I recently added a job to keep an eye on my IP and warn me if it changes, so that I don't get locked out by my own fail2ban.
Cron is one of those Linux tools that just quietly does its thing in the background

This isn't a how-to-do-it post; in fact, I'm crap at that. It's just what I realised one day, using cron jobs on three different PCs and getting muddled sometimes.

Why Organising Scripts Matters

When you start writing cron jobs, it’s easy to end up with a mess of .sh files. So I put them all in one folder. Also, at first, I had a script called rsync_nextcloud.sh. Months later, I couldn’t remember where it was syncing to without opening the script to see the correct path.

So I renamed it to: rsync_nextcloud_to_BackUp2.sh Okay, it's not rocket science, but I didn't think about that then .....
Much clearer — BackUp2 is one of my backup HDDs. I should have named it properly from the beginning!

I keep all my shell scripts in one folder on each computer. Mine are for example: ~/Documents/My_SH_files/

You can create this folder anywhere, name it whatever you like.

Inside my My_SH_files folder, I have scripts like:

Making Your Script Executable
Once you’ve written your .sh file, you need to make it executable: chmod +x /path/to/your/script.sh

Adding Jobs to Cron

To actually run your script on a schedule, you need to edit your crontab.

Use terminal:
crontab -e        # runs jobs as your user 
sudo crontab -e   # runs jobs as root
 👉 Use your user crontab for personal/home directory scripts.
 👉 Use root’s crontab if the job needs access to system folders or external drives with root permissions.
I cheat on my Arch PC they are all in sudo crontab -e

Here are two of mine:
10 10 * * 6 /home/xxx/Documents/My_SH_files/rsync_nextcloud_to_Backup2.sh
*/30 * * * * /home/xxx/Documents/My_SH_files/ip_change_alert.sh

For info: The numbers at the start are the schedule. If you’re not sure how to set them, check out this site https://crontab.guru/

Don't forget. If you rename the sh file, you must rename the cron job as well; otherwise, it won't run.

ChatGPT
To save some work. Here's a trick for you. Run a simple ls command in terminal
~/D/My_SH_files> ls
Then, in crontab -e copy the results
Copy both the results into ChatGPT and ask it to compare the titles

ChatGPT "Can you compare my sh files to my cron jobs to check I haven't made any errors in the titles?"
I got this result : All scripts you listed have a corresponding cron job, no mismatches.

Keeping an eye on my jobs

On each of my computers, I also use a Conky script that shows me my current crontab jobs right on the desktop. Nothing special, just so that I have a visual reminder of what’s running and when.

Final Thoughts

With a bit of organisation — keeping your scripts in one place, naming them clearly, and setting up your crontab properly — cron becomes a powerful, easy backup tool.

I've already written a post a couple of years ago on my WordPress blog explaining how to use cron itself: Although re-reading it, I see that maybe I need to update it a little :)
👉 https://www.minty95.com/using-cron-to-back-up-files-or-folders/