You may need to execute a bash script to automate a few procedures in your website. This operation is, for example, required by Magento updates that are usually executed launching a script .sh.
The majority of shared hosting plans, are not provided with ssh access: you can solve the problem uploading your own script in your website and let the cron launch it.
Let's suppose that you own a "script.sh" script and that you upload it in your website's home: /home/username/script.sh.
To execute the script, executions permissions (755) will be required: this operation can be processed via FTP or File Manager in your cPanel.
You need to set the cron correctly, as you can see in the image below, to let it start one or several times, according to your needs.