Rsync 3.1.3 Description:
rsync is an open source command-line utility, designed as a replacement for rcp (and scp), but with many more features. It uses the "rsync algorithm," which provides a very fast method for remote files into sync. rsync project does its job by sending just the differences in the files across the link, without requiring that both sets of files are present at one of the ends of the link beforehand. With rsync, users will be able to update entire file systems and directory trees, can use SSH, RSH or direct sockets as the transport, mirroring support via anonymous rsync, and optionally, preserve symbolic links, file ownership, hard links, permissions, times and devices.