rdiff-backup is 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 rdiff-backup-fs.
USE flags for app-backup/rdiff-backup Local/remote mirroring+incremental backup
||Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces|
emerge --ask --verbose --tree rdiff-backup
rdiff-backup path/to/source path/to/backup/destination
To backup again, simply run the exact same command; each increment will be individually accessible.
The cp command can simply be used to copy a file from a backup created with rdiff-backup.
See rdiff website for more examples.
0 3 * * * rdiff-backup /path/to/source /path/to/backup/destination