Duplicati is the only portable backup program, able to send backups in encrypted form to another computer or MS Live SkyDrive using one of several methods (WebDAV, FTP, SFTP/SCP/SSH, Amazon S3, Rackspace CloudFiles, USB ...

rsync is a software application for Unix which synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate. An important feature of rsync not found ...