JSON Patch test: how not to overwrite a price after someone else's change
Practical guide to RFC 6902: place a test before replace, reproduce fresh and stale prices, verify atomic failure and JSON type differences on CPython 3.12.
Денис
8 minViews5
GENERAL IT · JOURNAL
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sha256sum --check: how to verify backup integrity
Reproducible SHA-256 manifest verification: successful match, single-byte alteration, missing file, strict mode, and boundaries — why a matching hash does not prove recoverability.
Михаил
5 minViews4
application/problem+json: How Not to Mistake an HTML Error for JSON
A practical guide to RFC 9457: first check the HTTP status and Content-Type, then safely parse Problem Details. Using Python 3.12, we reproduce a correct 422 response, HTML from a gateway, broken JSON, incorrect types, and status mismatches.
Денис
8 minViews9
rsync --dry-run: How to See Deletions and Overwrites Before Synchronization
A practical guide to safely checking rsync: read the itemized output, spot deleted files, and detect content changes when size and timestamp are identical.
Михаил
6 minViews4
ETag and If-Match: How to Avoid Overwriting Stock During Dual API Updates
A practical guide to protecting APIs from stale records: two clients read the same product, the first updates the stock, the second receives a 412 and retries the update only after a new GET.
Денис
11 minViews5
Permission denied: How to find a directory without search permission using namei
Practical diagnosis of Permission denied in Linux: decompose the path with namei -l, locate an intermediate directory lacking search permission x, and verify a targeted fix without recursive chmod.
Михаил
6 minViews5
429 Retry-After: Seconds or Date — Checking the API Client's Wait Time
Practical analysis of two Retry-After formats for HTTP 429: parsing seconds and HTTP dates, limiting wait time, and testing six boundary cases in Python 3.12.
Денис
5 minViews4
How to Verify fstab Before Reboot: findmnt Without mount -a
We verify the candidate fstab using findmnt --verify, analyze return codes and method limitations without mounting disks or altering the active configuration.
Михаил
6 minViews9
Process Terminated Abruptly: How to Confirm OOM in Ubuntu 24.04
Check the kernel log, systemd-oomd, and cgroup limits to distinguish memory exhaustion from similar failures and preserve facts before changes.
Михаил
5 minViews8
Why Businesses Lose Customers Online
We examine what hinders small businesses from attracting customers online—from outdated websites to weak positioning
Steal Time on VPS: How to Check CPU Wait in Linux
The st column helps detect CPU wait at the virtualization level. A quick vmstat check, its result thresholds, and data for a targeted inquiry to the provider.
Михаил
5 minViews5
How to Validate a JSON File with jq Before Importing to a Store
Check syntax, empty files, multiple documents in sequence, and the top-level type. Read commands with verified examples for jq 1.7.
Денис
4 minViews13
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