fsck tips — authorized filesystem check literacy

Snapshot

Tip checklist (authorized only)

1. Confirm you may run fsck on the lab host (syllabus box you own; check/repair needs root on the target device; prefer unmounted lab filesystems).
2. Prefer documenting who / why / ticket before any repair — never run destructive repair on production without change control.
3. Record short factual notes; quote short Evidence (device name + exit code — never secrets).
4. Optional: UUID/LABEL peer → blkid-uuid-tips.
5. Optional: create peer → mkfs-tips.
6. Prefer disposable lab VMs and throwaway loop devices (losetup-tips) for fsck drills; quote non-secret labels afterward as Evidence.
7. Prefer fsck -N (what would run) / fsck -n (read-only check) before authorized repair — refuse unauthorized foreign-disk cookbooks.
8. Stop at literacy — no attack or unauthorized disk-bypass cookbooks.

Allowed framing

• Classroom labs reviewing fsck -N /dev/loopN then authorized fsck -n on disposable unmounted lab filesystems.
• Binding short factual notes as Evidence (device + exit code — no secrets).
• Documenting expected vs observed check results for authorized notes.
• Comparing fsck ↔ blkid / mkfs / df / wipefs peer tip pages under one binder.
• Testing syllabus-approved lab filesystem check only when change control authorizes that drill on lab resources.

Scope we will not cover

• No crack/pirate/keygen via fsck.
• No intentional unauthorized check/repair against foreign filesystems.
• No secret-theft or credential harvesting against hosts you do not own.
• No cookbooks that use fsck as an attack step against production without authorization.
• No fsck framed as a disk-bypass against systems you do not own.

Beginner path (authorized only)

1. Obtain one syllabus-approved disposable lab host with util-linux/e2fsprogs available.
2. Prefer a throwaway loop device (losetup-tips) with a known lab filesystem before any fsck.
3. With authorization, unmount then run fsck -N / fsck -n <lab-dev>; quote selected device/exit-code labels as Evidence.
4. Optional: peer tip pages above when the syllabus asks.
5. Stop at literacy — no attack or unauthorized disk-bypass cookbooks.

Practical notes for authorized labs

• fsck dispatches to filesystem-specific checkers (e2fsck, xfs_repair via fsck.xfs wrappers, etc.) — keep Evidence labels distinct by type.
• Pair with blkid-uuid-tips when the syllabus zooms on type detection before check.
• Read-only -n / dry -N are great drills — document selected exit codes without dumping unrelated privileged state.
• Prefer documenting device names and exit codes the syllabus authorized.
• Never commit fsck dumps with secrets or proprietary disk serials to git — even for labs.

FAQ-aligned refusals (quick)

• Foreign-filesystem check/repair → refuse.
• Unauthorized disk-bypass / hostile-repair attack cookbooks → refuse.
• Attack/credential-theft framing → refuse.

For legal, authorized and educational use only.

FAQ

Sources