What does the RSYNC flag -r facilitate?

The RSYNC flag -r is used to enable recursive copies of directories and their contents. This means that when the -r option is specified, RSYNC will not only copy the specified directory but also all its subdirectories and files, preserving the entire hierarchy of the data. This functionality is crucial when you need to back up or synchronize entire directory structures, ensuring that every file and folder is included in the operation. The recursive feature allows for an efficient and comprehensive replication of directories from one location to another, making it a fundamental option in data management tasks using RSYNC.