Which program is designed to copy files locally or remotely and is known for its speed?

The program that is designed specifically to copy files both locally and remotely, with a focus on speed and efficiency, is rsync. It is widely used for synchronizing files and directories between different locations. One of its key advantages is its ability to transfer only the differences between source and destination files. This incremental copying minimizes the amount of data transmitted, which significantly enhances speed, especially when working with large datasets.

Rsync also offers various features such as compression during transmission, support for resume capabilities in case of interrupted transfers, and the ability to copy files over SSH, making it a versatile and powerful tool for backup and file synchronization tasks.

In contrast, while other options like scp and sftp can copy files over secure channels, they do not incorporate the same degree of efficiency in transferring only the changes in files. Tar, commonly used for archiving, is not specifically a transferring tool and lacks the advanced features that rsync provides for synchronization. Thus, rsync stands out as the most appropriate choice for copying files quickly and effectively.