Helpers not working after moving from Xampp to Linux server

I've moved my first CI4 project from Xampp to my Linux server tonight.  I followed the directory structure from the configuration documentation (where everything except the contents of the "/public" folder sits outside of public_html and the "/public" contents go in the public_html folder).  I kept the entire directory structure intact from the Xampp configuration.  I changed the baseurl.  Everything works except for pages that call custom Helper functions; it's saying those functions are undefined (but they work fine in the Xampp build).  Would anyone have any idea why the system wouldn't be finding / seeing the Helper functions in the new environment, even though the directory structure is identical and all other functionality works? 

Check the filename. Is all characters are lowercase like array_helper.php ?

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Check the filename. Is all characters are lowercase like array_helper.php ?

Looks like that was the issue - thanks!  It's weird - some of the examples I saw in various places involved naming the custom Helper files with capitalized first word, underscore, then lowercase "helper.php" (e.g. Example_helper.php), but then calling the file all lowercase in the controller like this:  helper(example);  I just changed the file names to all lowercase and the errors are gone.  I appreciate it!

Linux file system is case sensitive. So if you code helper('example'), the filename must be example_helper.php.

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