blog/content/posts/2022/06/legdur.md

title	date	tags
legdur - keep your legacy durable	2022-06-25	cli rust

Hey, I wrote a thing. Thing being a piece of software. I have a collection of photos & documents that I really care about. I synch them between computers using syncthing and also run backups regularly. What I didn't have was a way to quickly detect bitrot.

Enter legdur

legdur is a simple CLI program to compute hashes of large sets of files in large directory structures and compare them with a previous snapshot. Think having your photo collection you acquired over time and worrying about bitrot.

Installation

cargo install legdur --force should get you there on a system that has Rust installed already.

Usage

legdur path/to/a/directory/

working:

legdur ~/documents
2022-06-25T06:45:51.000214Z  INFO legdur: scanning '/home/cyryl/documents'
2022-06-25T06:45:51.044471Z  INFO legdur: list of files acquired, calculating hashes...
█████████████████████████████████████████████████████████████░░░░░░░░░░░░░░░░ 2788/3190

finished:

2022-06-25T06:49:23.776229Z  INFO legdur: hash calculation complete
2022-06-25T06:49:23.784499Z  INFO legdur: /home/cyryl/documents/legdur.db saved
2022-06-25T06:49:23.792585Z  INFO legdur: comparing /home/cyryl/documents/legdur.db with /home/cyryl/documents/legdur.old
2022-06-25T06:49:23.826548Z  WARN legdur: /home/cyryl/documents/legdur.db: 395f65f5727f946c0208f79cfe1f3de1bd81e491bb7631ba6f41fc578d3db368 -> 7d1b9748ed291eb6874c91917b5619eb8e1410e7cbfd37a517c5bd4ddf8c7895
2022-06-25T06:49:23.826715Z  WARN legdur: /home/cyryl/documents/legdur.old: e56cf4f6b7fdc2daa3ca3430e8e64bf9d042f1c0e465dcd452986709cb25f7d8 -> 395f65f5727f946c0208f79cfe1f3de1bd81e491bb7631ba6f41fc578d3db368

How it works

• it will compute a hash of each file present in the directory structure (it works recursively).
• if previously computed legdur.db exists it will compare the current state of the world to the one represented by legdur.db and output any differences. Only files that changed or got deleted get printed out, additions are not.
• it will move the current legdur.db to legdur.old and write the new state of the world to a new legdur.db

Contact & contributions

• Let me know if you'd like to hack on this by contacting me on legdur@cyplo.dev or via cyplo@todon.nl on Mastodon.
• Discuss on lobsters

Sources

hg clone https://hg.sr.ht/~cyplo/legdur