Name Upper with calibre/sqlite but Lower with ls -ld under Unix

[Doum]

I'm having an issue with Calibre 8.16 directories.
Some Unix-based book names begin with a lowercase letter, while in the SQLite database (metadata.db) and within Calibre itself, they all begin with an uppercase letter.

This is a very rare occurrence and likely results from remnants of older versions, but Calibre (via maintenance) never detects it. This causes conflicts between Unix and Windows. Is there any way to control this?

example
ls -ld [a-z]* ==> 'une troublante coincidence (1000)'

sqlite> select title, from books where id=1000;
Une troublante coincidence|1000

[theducks]

Be very careful *fixing* folder or file names outside of Calibre

Have you tried the Quality Check Plugin: Fix: Check and Rename Book paths

That is Calibre making changes.

Also Case differences are because the Entries in Calibre are that way.
Open the Tag Browser: Authors: right click: Manage <this is where you can see and adjust the Authors case and spelling and everything follows.

As to Titles : Again Quality check: Check metadata, check titles for case (at the bottom). Once you have the problem kids discovered, select All: Tap 'E' (Metadata edit bulk mode): The form has change Title case to: (and update the sort)

[kovidgoyal]

Dont share a library folder between unix and windows, its a recipe for data loss as the two have very different semantics. If you do insist on doing so make the folder of the calibre library case insensitive on Linux, that will at least remove one source of semantic differences.

[Doum]

Thank you for your replies. The "quality check" is quite useful, but I'm going to use an SQLite script combined with "ls" to verify the consistency of the authors/titles with my actual file paths.
For your information, I encountered errors with the PHP function `imagecreatefromjpeg`. I passed it the path retrieved via an SQL query, but it generated a "Failed to open stream: No such file or directory" error because the actual path had a different lowercase/uppercase character. (I use it to create minicovers from the cover.jpg file in Calibre files.)