DuckDB runs full SQL against files straight from the shell:
Shell
duckdb -c "SELECT region, sum(amount) FROM 'sales.csv' GROUP BY region"
Converting formats is one command:
Shell
duckdb -c "COPY (FROM 'sales.csv') TO 'sales.parquet'"
Tip
When a one-liner grows past one line, that's the cue to move it
into a versioned .sql file — the shell is for looking, the repo
is for keeping.