clawbot
6a0dfa9f2c
`make try` ran against a fixed directory on one person's machine. It failed for anyone else, and where that directory existed it rewrote the checksum attributes and modification times of real files. It now writes three small files into a new directory from `mktemp -d`, runs the same sequence of commands on it, and removes it with an EXIT trap. All steps run in one shell, so the trap also removes the directory when a step fails. `TODO.md`: the `try` sentence leaves Next Step and is recorded under Completed Steps. Model: opus-5-5
attrsum is a Go 1.22 command-line utility that adds, updates, verifies, and clears per-file file content checksums stored in extended attributes (xattrs) on macOS (APFS) and Linux, released under the WTFPL v2.
Original release 2025-05-08.
Current version 1.0 (2025-05-08).
Getting Started — Quick Build
# prerequisites: Go 1.22+
git clone https://git.eeqj.de/sneak/attrsum.git
cd attrsum
go build -o attrsum .
Install
go install git.eeqj.de/sneak/attrsum@latest # into GOPATH/bin or $(go env GOBIN)
Semantic Versioning 2.0.0 is used for tags.
Usage
# add checksum & timestamp xattrs to every regular file under one or more paths
attrsum sum add DIR1 DIR2 file.txt
# update checksum only when file mtime is newer than stored sumtime
attrsum sum update DIR1 DIR2
# verify checksums, stop on first error
attrsum check DIR1 DIR2
# verify every file, reporting each result, keep going after errors
attrsum -v check --continue DIR1 DIR2
# remove checksum & timestamp xattrs
attrsum clear DIR1 DIR2
# read paths from stdin (use - as argument)
find /data -name "*.jpg" | attrsum sum add -
# quiet mode (suppress progress bar and summary)
attrsum -q sum add DIR
| xattr key | meaning |
|---|---|
user.berlin.sneak.app.attrsum.checksum |
base-58 multihash (sha2-256) |
user.berlin.sneak.app.attrsum.sumtime |
RFC 3339 timestamp of checksum |
Flags:
-v, --verbose— per-file log output-q, --quiet— suppress all output except errors (no progress bar or summary)--exclude PATTERN— skip paths matching rsync/Doublestar glob--exclude-dotfiles— skip any path component that starts with.
All commands display a progress bar with ETA and print a summary report to stderr on completion (unless --quiet is specified).
attrsum never follows symlinks and skips non-regular files (sockets, devices, …).
Why?
Apple APFS and Linux ext3/ext4 store no per-file content checksums, so
silent data corruption can pass unnoticed. attrsum keeps a portable checksum inside each file’s xattrs, providing integrity
verification that travels with the file itself—no external database
required. Now you can trust a USB stick didn't eat your data.
TODO
Future improvements under consideration:
- Dry-run mode (
--dry-run,-n) — show what would be done without making changes - JSON output (
--json) — machine-readable output for scripting and integration - Parallel processing (
-j N) — use multiple goroutines for faster checksumming on large trees - Exit code documentation — formalize and document exit codes for scripting
Contributing
- Author & maintainer: sneak – sneak@sneak.berlin
- Issues / PRs: https://git.eeqj.de/sneak/attrsum/
- Code must pass
go vet,go test ./..., andgo fmt. - No CLA; contributions are under WTFPL v2.
Community & Support
Bug tracker and wiki are in the Gitea repo linked above.
No formal Code of Conduct; be excellent to each other.
License
Everything is permitted. See WTFPL v2.