rsync is a powerful file synchronization tool used to efficiently transfer and synchronize files between different locations, whether on the same machine or across a network. It minimizes data transfer by only copying the differences between the source and the destination, making it faster and more efficient than traditional copy methods. This utility is commonly used for backups, mirroring data, and maintaining file consistency across multiple systems. rsync supports various options, such as compression and encryption, allowing users to customize their file transfer processes according to their needs.