ICHKSUM(1)

✨ NAME ✨

okay so bestie, welcome to ichksum(1) — that's ICHKSUM(1), User Commands, and it's an iRODS iCommand. The name is literally:

ichksum — an iRODS iCommand.

That's the whole vibe: checksum business, iRODS edition. 💅

🌸 SYNOPSIS 🌸

ichksum [-haMrvV] [-f|K|--verify] [-n replNum|-R resource] [--silent]

💖 DESCRIPTION 💖

The thing you're pointing it at is:

dataObj|collection ...

Checksum one or more data objects or collections. ✨

The checksum algorithm used by this function is determined by the client and server's configuration, but defaults to SHA256. Checksum values are only calculated on the part of a replica indicated by the size stored in the catalog, not necessarily the entirety of the file under management.

lowkey important, bestie: that "part of a replica indicated by the size stored in the catalog" detail is not a suggestion — it's the actual rule. 🫶

There are two modes of operation:

• Lookup/Update (default): Computes and updates checksum information.
• Verification: Detects and reports issues related to checksum information.

🔍 Lookup/Update mode 🔍

In Lookup/Update mode, the following operations are performed:

1. Compute a new checksum and updates the catalog.
2. Reports if the replicas do NOT share identical checksums.

Lookup/Update mode will process the highest voted replica unless -a is present. If -f is not present and the replica already has a checksum, that checksum will be printed to the terminal. If a specific replica is targeted, step 2 is not performed.

Lookup/Update mode supports operations on replicas marked as good or stale.

🦋 Verification mode 🦋

In Verification mode, the following operations are performed:

1. Reports replicas with mismatched size information (physical vs catalog).
2. Reports replicas with missing checksums. (Halts if missing checksums are found)
3. Reports replicas with mismatched checksums (computed vs catalog).
4. Reports if the replicas do NOT share identical checksums.

Verification mode operates on all replicas unless a specific replica is targeted. If a specific replica is targeted, step 4 is not performed.

Verification mode supports operations on replicas marked as good.

Operations that target multiple replicas will only affect replicas that are marked as good. This means intermediate, locked, and stale replicas will be ignored.

Operations that target a specific replica are allowed to operate on stale replicas unless stated otherwise.

🎀 OPTIONS 🎀

• -f — Computes and stores a checksum for one or more replicas. This option always results in a catalog update.
• -a — Apply operation to all good replicas.
• -K, --verify — Verifies the state of the checksums for one or more replicas.
• --no-compute — When used with -K, no checksums are computed. This option causes step 3 of -K to be skipped. This option is provided as a way to avoid long running checksum computations when a size check is adequate.
• -M — Run the command as an administrator.
• -n REPLICA_NUMBER — The replica number of the replica to checksum or verify.
• -R RESOURCE_NAME — The root resource that contains the replica to checksum or verify.
• -r — Checksum data objects recursively.
• --silent — Suppresses output of checksums and output related to -r.
• -v — Verbose.
• -V — Very verbose.
• -h — Prints this message.

And the help tail also shows iRODS Version 5.0.2 and ichksum, so there's that little detail too. 💜

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💖 cute sign-off bestie: this page comes from ichksum iRODS-5.0.2, dated January 1980 — mwah, periodt. 🎀