How to change the case of a file on a case insensitive OS

Imagine you're in a directory with a single file named file.jpg.

On a case-insensitive system, this command (renaming file.jpg to File.jpg) will fail as the target file already exists.

$ renamer --find file --replace File file.jpg

You can override this behaviour by passing --force.

$ renamer --find file --replace File file.jpg --force

The target file is now File.jpg.