Command Reference

Command Reference

Tier: Beginner

Every qsv command, grouped by category. This page is the index — each row links to the category page (workflow-level discussion + non-trivial real-world example) and to the canonical per-command help in /docs/help/ (flags, arguments, full examples).

The exact set of commands in your binary depends on the variant and its enabled feature flags — run qsv --list to see what's available.

How to read this table. The category page tells you when to reach for a command and how it composes. The /docs/help/<cmd>.md page tells you exactly which flags exist. Use both.

Legend

Commands inherit symbols from the README legend. The most useful ones to know:

• 📇 Faster with an index. Create one with qsv index <file>.
• 🚀 Multithreaded by default (even without an index).
• 🏎️ Multithreaded when an index exists.
• 🐻‍❄️ Powered/accelerated by Polars.
• 🤯 Loads entire file into memory (consider streaming alternatives for huge files).
• 🪄 "Automagical" — uses the stats / frequency cache to work smarter.
• 📚 Supports runtime lookup tables.
• 🌐 Has remote / URL options.
• 🔣 Requires UTF-8 input.
• 👆 Has the powerful column selector syntax — see select.
• ✨ Behind a feature flag — see Binary Variants and docs/FEATURES.md.

Selection & Inspection — category page

Daily-driver commands for looking at and slicing a CSV.

Command	Symbols	One-liner	Help
headers	🗄️	Show column names (and union across many files)	docs/help
count	📇🐻‍❄️🏎️	Row count (instant with an index)	docs/help
sample	📇🏎️🌐	Random sample with 8 methods (reservoir, indexed, bernoulli, systematic, stratified, weighted, cluster, timeseries)	docs/help
slice	📇🗃️🏎️	Slice by row range	docs/help
select	👆	Pick / re-order / drop columns	docs/help
search	📇🏎️👆	Filter rows by regex	docs/help
searchset	📇🏎️👆	Run many regexes in a single pass (PII scanning)	docs/help
flatten		Show one record per line (vertical view)	docs/help
table	🤯	Elastic-tab table view + leftendtab / Fixed-Width output	docs/help
lens	✨🗃️🐻‍❄️🖥️	Interactive viewer (csvlens) — CSV, Parquet, Arrow, JSONL	docs/help
clipboard	✨🖥️	Read from / write to OS clipboard	docs/help
sniff	📇🤖🌐	Infer delimiter, headers, schema, MIME type — even for remote files	docs/help

Transform & Reshape — category page

Clean, rename, sort, reshape — the pre-analysis layer.

Command	Symbols	One-liner	Help
apply	✨📇🧠🤖🚀🔣👆	String/date/math/currency/NLP transformations	docs/help
applydp	📇🚀🔣👆	Slim apply for DataPusher+ (qsvdp only)	docs/help
behead		Drop the header row	docs/help
cat	🗄️	Concatenate CSVs by row or column	docs/help
datefmt	📇🚀👆	Reformat dates (19 input formats recognized)	docs/help
edit		Update a single cell at row × column	docs/help
enum	👆	Add a row-number / UUID / constant column	docs/help
explode	🔣👆	Split a multi-valued column into multiple rows	docs/help
fill	👆	Fill missing values (forward, backward, constant)	docs/help
fixlengths		Pad or truncate ragged rows	docs/help
fmt		Reformat delimiters / terminators / quoting	docs/help
implode	😣👆	Inverse of explode — collapse rows by key	docs/help
input		Normalize: encoding, comments, trim, skip preamble	docs/help
pseudo	🔣👆	Pseudonymize a column with incremental IDs	docs/help
rename		Rename columns	docs/help
replace	📇🏎️👆	Regex replace across fields	docs/help
reverse	📇🤯	Reverse row order (constant memory with index)	docs/help
safenames		Make column names DB-/CKAN-safe	docs/help
sort	🤯🚀👆	Lex / natural / numeric / unique / random sort	docs/help
sortcheck	👆	Verify sort order; report duplicates and breaks	docs/help
transpose	🤯👆	Swap rows ↔ columns	docs/help

Aggregation & Statistics — category page

Numbers, distributions, dedup, ext-* commands.

Command	Symbols	One-liner	Help
stats	📇🤯🏎️👆🪄	47 summary stats + guaranteed type inference	docs/help
moarstats	📇🏎️	+55 more stats (outliers, robust, bivariate)	docs/help
frequency	📇😣🏎️👆🪄	Frequency distribution per column	docs/help
pragmastat	📇🤯🪄	Pragmatic stats (date/datetime aware)	docs/help
dedup	🤯🚀👆	Drop duplicate rows (streaming & full)	docs/help
extdedup	👆	On-disk dedup for files > RAM	docs/help
extsort	📇🚀👆	Multithreaded external merge sort	docs/help

Joins & Set Ops — category page

Combine, exclude, partition, split.

Command	Symbols	One-liner	Help
join	📇😣👆	In-memory inner/outer/cross/anti/semi joins	docs/help
joinp	✨🐻‍❄️🚀🪄	Polars-powered: non-equi, asof, larger-than-RAM	docs/help
exclude	📇👆	Remove rows of one CSV from another	docs/help
partition	👆	Split into one file per value of a column	docs/help
split	📇🏎️	Split by rows / chunks / size (multithreaded with index)	docs/help

SQL & Polars — category page

Polars LazyFrame, SQL, pivots, score-before-run.

Command	Symbols	One-liner	Help
sqlp	✨📇🗄️🐻‍❄️🚀🪄	Polars SQL across CSVs/Parquet/JSONL/Arrow	docs/help
joinp	✨🐻‍❄️🚀🪄	Polars joins (see Joins category)	docs/help
pivotp	✨🐻‍❄️🚀🪄	Pivot with smart aggregation auto-selection	docs/help
scoresql	✨🐻‍❄️🪄	Score a SQL query BEFORE running it (Polars / DuckDB modes)	docs/help

Validation & Schema — category page

Infer, validate, sniff.

Command	Symbols	One-liner	Help
validate	📇🗄️🚀🌐📚	JSON Schema 2020-12 validation (up to 780k rows/sec)	docs/help
schema	📇😣🐻‍❄️🏎️👆🪄	Infer JSON Schema 2020-12 or Polars schema	docs/help
sniff	📇🤖🌐	Quick metadata inference (see Selection category)	docs/help

Conversion & I/O — category page

Move between formats: Parquet, Excel, ODS, JSON, JSONL, SQLite, Postgres, GeoJSON, Snappy.

Command	Symbols	One-liner	Help
excel	🚀	Export Excel/ODS sheets to CSV	docs/help
to	✨🗄️🐻‍❄️🚀	CSV → Parquet, SQLite, Postgres, Excel, ODS, Data Package	docs/help
json	👆	JSON array → CSV	docs/help
jsonl	🚀🔣	JSONL → CSV	docs/help
tojsonl	📇😣🗃️🚀🔣🪄	CSV → JSONL with smart type inference	docs/help
snappy	🚀🌐	Streaming Snappy compress/decompress	docs/help
geoconvert	✨🌎	Spatial formats ↔ CSV (GeoJSON, SHP, SVG…)	docs/help
prompt	✨🐻‍❄️🖥️	OS file-picker dialog	docs/help
clipboard	✨🖥️	OS clipboard I/O (see Selection category)	docs/help

Geospatial — category page

Command	Symbols	One-liner	Help
geocode	✨📇🧠🚀🌐🔣👆🌎	Forward / reverse geocode (Geonames + Maxmind), 360k/sec	docs/help
geoconvert	✨🌎	Spatial format conversions	docs/help

HTTP & Web — category page

Command	Symbols	One-liner	Help
fetch	✨📇🧠🌐	HTTP GET per row, HTTP/2 flow control, jaq, Redis/disk cache	docs/help
fetchpost	✨📇🧠🌐⛩️	HTTP POST per row, MiniJinja body templating	docs/help

Scripting (Luau / Python) — category page

Command	Symbols	One-liner	Help
luau	✨📇🌐🔣📚	Luau 0.720 DSL: BEGIN/MAIN/END, lookup tables, random access	docs/help
py	✨📇🔣	Python expression per row (requires Python 3.10+)	docs/help
foreach	✨	Run a shell command per row	docs/help
template	📇🚀🔣📚⛩️	MiniJinja-render CSV rows into any text format	docs/help

Indexing, Compression & Diff — category page

Performance primitives.

Command	Symbols	One-liner	Help
index		Build an index for instant random access	docs/help
diff	🚀	Diff two CSVs (1M × 9 in <600 ms)	docs/help
blake3	🚀	BLAKE3 hash for cache keys / pipeline gating	docs/help
extsort	📇🚀👆	External merge sort (see Aggregation category)	docs/help
extdedup	👆	On-disk dedup (see Aggregation category)	docs/help
snappy	🚀🌐	Streaming Snappy compression (see Conversion category)	docs/help

AI & Documentation — category page

Command	Symbols	One-liner	Help
describegpt	📇🗃️🤖🌐🪄📚⛩️	Neuro-symbolic data dictionary + SQL RAG via any OpenAI-compatible LLM	docs/help
color	✨🤯🐻‍❄️🖥️	Pretty colorized table that fits the terminal	docs/help
pro		Bridge to the qsv pro API	docs/help

Built-in

Command	One-liner
help	Show qsv's top-level usage (run qsv help or qsv --help)

See also

• README — full command catalog with legend
• /docs/help/TableOfContents.md — alphabetical command index
• Cookbook — task-oriented recipes
• Binary Variants — which commands exist in which build
• Performance Tuning
• Environment Variables