Borg (previously called Attic) is deduplicating backup software for various Unix-like operating systems.

[5] Many issues in Attic have been fixed in this fork, but backward compatibility with the original program has been lost (a non-reversible upgrade process exists).

[6] The next major Borg version, 2.0, in beta since 2022, will break backward compatibility again, requiring a non-reversible upgrade process.

Borg offers efficient, deduplicated, compressed and (optionally) encrypted and authenticated backups.

Internally it represents the files in an archive as a stream of metadata, similar to tar and unlike tools such as git.