Duplicity incrementally backs up files and directories by encrypting
tar-format volumes with GnuPG and uploading them to a remote (or local)
file server. In theory many remote backends are possible; right now
local, ssh/scp, ftp, rsync, HSI, WebDAV, and Amazon S3 backends are
written.

Because duplicity uses librsync, the incremental archives are space
efficient and only record the parts of files that have changed since
the last backup. Currently duplicity supports deleted files, full unix
permissions, directories, symbolic links, fifos, etc., but not hard
links.