Rdiff-backup

is Article description::a GPL-licensed incremental backup utility based on librsync; it stores changes to files instead of entire duplications. This can greatly reduce storage requirements for backups. The resultant incremental data can be viewed and restored from as if it were whole file backups via FUSE-based.

Backup
To backup again, simply run the exact same command; each increment will be individually accessible.

External resources

 * rdiff-backup tutorial at howtoforge.com
 * Unattended rdiff-backup HOWTO
 * A Debian based tutorial at linode.com