UnionFS

UnionFS is a technology used in computing that allows multiple file systems or directories to be combined into a single, unified view. Think of it as stacking several folders on top of each other, where the system presents the combined contents as one. Changes made can be stored in a writable layer without altering the original, read-only layers underneath. This is useful for creating flexible, layered systems such as live Linux distributions, where core files remain immutable but users can add or modify files seamlessly. It enables efficient management and customization of complex file structures without duplication.