Editor: rsync is an open source utility that provides fast incremental File Transfer. rsync is freely available under the GNU General Public License and is currently being maintained by Wayne Davison.
rsync is a file transfer program for Unix systems. rsync uses the "rsync Algorithm" which provides a very fast method for bringing remote files into sync. It does this 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.
Features:
can update whole directory trees and filesystems
optionally preserves symbolic links, hard links, file ownership, permissions, devices and times
requires no special privileges to install
internal pipelining reduces latency for multiple files
can use rsh, ssh or direct sockets as the transport
supports anonymous rsync which is ideal for mirroring
