How to use
- Copy the installation command and review the source package before installing it in your own agent environment.
- Check the source document for required tools, credentials and supported hosts.
- Describe your input and desired deliverable; review the output against the source material.
npx skills add https://github.com/duckdb/duckdb-skills --skill convert-fileBefore you start
- Installation does not include a model subscription, API allowance or permission to access your files.
- Repository stars and installation counts describe activity, not an independent quality or security test.
Rendered from the source repository. Headings, examples, code, tables, links, and referenced images are preserved.
You are helping the user convert a data file from one format to another using DuckDB.
Input file: $0 Output file: ${1:-}
Step 1 — Resolve input and output
Input: $0. If it's a bare filename (no /), resolve to a full path with find "$PWD" -name "$0" -not -path '*/.git/*' 2>/dev/null | head -1.
Output: If $1 is provided, use it as the output path. If not, default to the same stem as the input with a .parquet extension (e.g., data.csv → data.parquet).
Infer the output format from the output file extension:
| Extension | Format clause |
|---|---|
.parquet, .pq | (default, no clause needed) |
.csv | (FORMAT csv, HEADER) |
.tsv | (FORMAT csv, HEADER, DELIMITER '\t') |
.json | (FORMAT json, ARRAY true) |
.jsonl, .ndjson | (FORMAT json, ARRAY false) |
.xlsx | (FORMAT xlsx) — requires INSTALL excel; LOAD excel; |
.geojson | (FORMAT GDAL, DRIVER 'GeoJSON') — requires LOAD spatial; |
.gpkg | (FORMAT GDAL, DRIVER 'GPKG') — requires LOAD spatial; |
.shp | (FORMAT GDAL, DRIVER 'ESRI Shapefile') — requires LOAD spatial; |
Step 2 — Convert
Run a single DuckDB command. Prepend extension loads as needed based on both the input and output formats.
duckdb -c "
<EXTENSION_LOADS>
COPY (FROM '<INPUT_PATH>') TO '<OUTPUT_PATH>' <FORMAT_CLAUSE>;
"For remote inputs (s3://, https://, etc.), prepend the same protocol setup as read-file:
| Protocol | Prepend |
|---|---|
s3:// | LOAD httpfs; CREATE SECRET (TYPE S3, PROVIDER credential_chain); |
gs:// / gcs:// | LOAD httpfs; CREATE SECRET (TYPE GCS, PROVIDER credential_chain); |
https:// / http:// | LOAD httpfs; |
If the user mentions partitioning (e.g., "partition by year"), add PARTITION_BY (col) to the format clause. This only works with Parquet and CSV output.
If the user mentions compression (e.g., "use zstd"), add CODEC 'zstd' for Parquet output.
Step 3 — Report
On success, report:
- Input file and detected format
- Output file, format, and size (
ls -lh) - Row count if quick to compute
On failure:
- `duckdb: command not found` → delegate to
/duckdb-skills:install-duckdb - Missing extension → install it and retry
- Input parse error → suggest the user check the input format or try
/duckdb-skills:read-filefirst to inspect it
