November 12, 2026 | macOS | Python 3.14.9
Fictional practice inputs. Commands run from the extracted practice packs.

$ python3 csv_delivery.py compare duplicate.csv changes-after.csv blocked --key record_id
Exit 1
STOP: Duplicate key: 002
If an output folder was created, do not use it without a completed summary.json.

$ python3 csv_delivery.py compare changes-before.csv changes-after.csv forward --key record_id
Exit 0
{
  "status": "PASS",
  "operation": "compare",
  "key_column": "record_id",
  "before_sha256": "911f58ca80b93f197a2b5450cfc4c60ea88f8d00cb6ca92e606a3d25ca191f13",
  "after_sha256": "971f77997cd8000801c7e459f12e1e62da3bdb4f1b748d74695d78c716182d91",
  "before_records": 7,
  "after_records": 7,
  "counts": {
    "added": 1,
    "removed": 1,
    "changed": 4,
    "unchanged": 2
  },
  "changed_fields": 5,
  "comparison": "exact decoded strings; case and whitespace significant"
}

$ python3 csv_delivery.py compare changes-after.csv changes-before.csv reverse --key record_id
Exit 0
{
  "status": "PASS",
  "operation": "compare",
  "key_column": "record_id",
  "before_sha256": "971f77997cd8000801c7e459f12e1e62da3bdb4f1b748d74695d78c716182d91",
  "after_sha256": "911f58ca80b93f197a2b5450cfc4c60ea88f8d00cb6ca92e606a3d25ca191f13",
  "before_records": 7,
  "after_records": 7,
  "counts": {
    "added": 1,
    "removed": 1,
    "changed": 4,
    "unchanged": 2
  },
  "changed_fields": 5,
  "comparison": "exact decoded strings; case and whitespace significant"
}

forward • rows for 002: [['002', 'status', 'open', 'paid'], ['002', 'amount', '20.00', '25.00']]

reverse • rows for 002: [['002', 'amount', '25.00', '20.00'], ['002', 'status', 'paid', 'open']]