Claude Haiku 5.5 (effort default (no --effort flag) · thinking on) on Write a robust backup rotation script (dry-run, spaces, exit codes, safe deletion)

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  "result": "`rotate.sh` is written, executable, and passes the behaviour checks I ran. It's at `./usecase-runner/runs/d07-claude-haiku/work/rotate.sh`. The directory is not a git repo, so I did not commit.\n\nWhat I verified:\n- **Usage errors (exit 2):** no args, one arg, unknown option, `--keep 0`, `--keep x`, and `--keep` with no value.\n- **Missing source (exit 3):** a nonexistent `SRC_DIR` fails with exit 3.\n- **`--help`:** prints usage to stdout and exits 0.\n- **Archive contents:** entries are `./`-relative and names with spaces work. `*.tmp` files and `.cache` directories are excluded at every depth. The archive is created with mode 0644.\n- **Retention:** with six older backups and `--keep 5`, the oldest is deleted. Files like `notes.txt`, `backup-bad.tar.gz`, and a matching-named directory are left alone.\n- **Dry-run:** prints `CREATE` and `DELETE` lines and changes nothing on disk.\n- **Destination inside source:** the archive excludes the destination directory, so it doesn't back up its own output.\n\nChoices I made where the spec was open:\n- An empty `BACKUP_NOW` counts as unset. A non-empty value that isn't `YYYYMMDD-HHMMSS` is a usage error (exit 2), because a malformed name would never match the retention pattern.\n- Runtime failures (tar, mv, mkdir) exit 1. The spec didn't assign a code to these.\n- `DEST_DIR` is created only in real runs, so `--dry-run` leaves no trace.\n- Retention includes the backup about to be created. If `BACKUP_NOW` is older than the N newest existing backups, the new file is deleted right away. That follows the \"keep only the N newest\" rule literally.\n- Only the `.cache` directory is excluded. A regular file named `.cache` is still archived.\n- Symlinks are stored as links, not followed.\n\nThe script uses GNU tar options (`--no-recursion`, `--null`, `--files-from=-`), so it needs GNU tar.",
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