ℹ️ NOTE: qsv is a fork of the popular xsv utility, merging several pending PRs since xsv 0.13.0's May 2018 release. On top of xsv's 20 commands, it adds numerous new features, 27 additional commands, 6
applysubcommands & 31applyoperations (for a total of 84). See FAQ for more details.
| Command | Description |
| --- | --- |
| apply^1 | Apply series of string, date, math, currency & geocoding transformations to a CSV column. It also has some basic NLP functions (similarity, sentiment analysis, profanity, eudex & language detection). |
| behead | Drop headers from a CSV. |
| cat | Concatenate CSV files by row or by column. |
| count[^2] | Count the rows in a CSV file. (Instantaneous with an index.) |
| dedup^3 | Remove duplicate rows (See also extsort & sortcheck commands). |
| enum | Add a new column enumerating rows by adding a column of incremental or uuid identifiers. Can also be used to copy a column or fill a new column with a constant value. |
| excel | Exports a specified Excel/ODS sheet to a CSV file. |
| exclude[^2] | Removes a set of CSV data from another set based on the specified columns. |
| explode | Explode rows into multiple ones by splitting a column value based on the given separator. |
| extsort[^5] | Sort an arbitrarily large CSV/text file using a multithreaded external merge sort algorithm. |
| fetch | Fetches data from web services for every row using HTTP Get. Comes with jql JSON query language support, dynamic throttling (RateLimit) & caching with optional Redis support for persistent caching. |
| fetchpost | Similar to fetch, but uses HTTP Post. (HTTP GET vs POST methods) |
| fill | Fill empty values. |
| fixlengths | Force a CSV to have same-length records by either padding or truncating them. |
| flatten | A flattened view of CSV records. Useful for viewing one record at a time.
e.g. qsv slice -i 5 data.csv \| qsv flatten. |
| fmt | Reformat a CSV with different delimiters, record terminators or quoting rules. (Supports ASCII delimited data.) |
| foreach[^1] | Loop over a CSV to execute bash commands. (not available on Windows) |
| frequency^2 | Build frequency tables of each column. (Uses multithreading to go faster if an index is present.) |
| generate[^1] | Generate test data by profiling a CSV using Markov decision process machine learning. |
| headers | Show the headers of a CSV. Or show the intersection of all headers between many CSV files. |
| index | Create an index for a CSV. This is very quick & provides constant time indexing into the CSV file. Also enables multithreading for frequency, split, stats and schema commands. |
| input[^2] | Read CSV data with special quoting, trimming, line-skipping and UTF-8 transcoding rules. Typically used to "normalize" a CSV for further processing with other qsv commands. |
| join[^2] | Inner, outer, cross, anti & semi joins. Uses a simple hash index to make it fast. |
| jsonl | Convert newline-delimited JSON (JSONL/NDJSON) to CSV. See tojsonl command to convert CSV to JSONL.
| lua[^1] | Execute a Lua 5.4 script over CSV lines to transform, aggregate or filter them. Lua is much faster than Python. |
| luajit[^1] | Execute a LuaJIT 2.0 (a Just-In-Time compiler for Lua 5.1) script over CSV lines to transform, aggregate or filter them. LuaJIT is even faster still than Lua. |
| partition | Partition a CSV based on a column value. |
| pseudo | Pseudonymise the value of the given column by replacing them with an incremental identifier. |
| py[^1] | Evaluate a Python expression over CSV lines to transform or filter them. Python's f-strings is particularly useful for extended formatting, with the ability to evaluate Python expressions as well.
Consider using the lua/luajit commands instead if you're having Python version issues (Python 3.6 and up supported, with Python 3.11 required on prebuilt qsv) as it's much faster, embedded, can do aggregations & has no external dependencies. |
| rename | Rename the columns of a CSV efficiently. |
| replace | Replace CSV data using a regex. |
| reverse[^3] | Reverse order of rows in a CSV. Unlike the sort --reverse command, it preserves the order of rows with the same key. |
| sample[^2] | Randomly draw rows (with optional seed) from a CSV using reservoir sampling (i.e., use memory proportional to the size of the sample). |
| schema[^4] | Infer schema from CSV data and output in JSON Schema format. Uses multithreading to go faster if an index is present. See validate command to use the generated JSON Schema to validate if similar CSVs comply with the schema. |
| search | Run a regex over a CSV. Applies the regex to each field individually & shows only matching rows. |
| searchset | Run multiple regexes over a CSV in a single pass. Applies the regexes to each field individually & shows only matching rows. |
| select | Select, re-order, duplicate or drop columns. |
| slice^2 | Slice rows from any part of a CSV. When an index is present, this only has to parse the rows in the slice (instead of all rows leading up to the start of the slice). |
| sniff[^2] | Quickly sniff CSV metadata (delimiter, header row, preamble rows, quote character, flexible, is_utf8, number of records, number of fields, field names & data types). |
| sort[^5] | Sorts CSV data in alphabetical, numerical, reverse or random (with optional seed) order (See also extsort & sortcheck commands). |
| sortcheck[^2] | Check if a CSV is sorted. With the --json options, also retrieve record count, sort breaks & duplicate count. |
| split^2 | Split one CSV file into many CSV files of N chunks. (Uses multithreading to go faster if an index is present.) |
| stats^2[^4] | Infer data type (Null, String, Float, Integer, Date, DateTime) & compute descriptive statistics for each column in a CSV (sum, min/max, min/max length, mean, stddev, variance, nullcount, quartiles, IQR, lower/upper fences, skewness, median, mode & cardinality). Uses multithreading to go faster if an index is present. |
| table[^3] | Show aligned output of a CSV using elastic tabstops. |
| tojsonl[^4] | Smartly converts CSV to a newline-delimited JSON (JSONL/NDJSON). By scanning the CSV first, it "smartly" infers the appropriate JSON data type for each column. See jsonl command to convert JSONL to CSV. |
| transpose[^3] | Transpose rows/columns of a CSV. |
| validate^2 | Validate CSV data with a JSON Schema (See schema command). If no jsonschema file is provided, validates if a CSV conforms to the RFC 4180 standard. |
For macOS and Linux (64-bit), you can quickly install qsv with Homebrew:
brew install qsv
Pre-built binaries for Windows, Linux and macOS are also available for download, including binaries compiled with Rust Nightly/Unstable (more info).
There are four variants of qsv:
* qsv enables all features valid for the target platform[^7]
* qsvnp enables all features EXCEPT python ("np" stands for "no python")
* qsvlite has all features disabled (~half the size of qsv)
* qsvdp is optimized for use with DataPusher+, with only DataPusher+ relevant commands and the self-update engine removed (~sixth of the size of qsv).
Alternatively, you can install from source by installing Rust
and installing qsv using Rust's cargo command[^6]:
For example, if you use Ubuntu, you can install the build-essential package. On macOS, you can get a C compiler by running $ xcode-select --install.
For Windows, this means installing Visual Studio 2022. When prompted for workloads, include "Desktop Development with C++",
the Windows 10 or 11 SDK, and the English language pack, along with any other language packs your require.
bash
cargo install qsv --features all_full
If you encounter compilation errors, ensure you have the Python development libraries installed and you're using the exact version of the dependencies qsv was built with by issuing:
bash
cargo install qsv --locked --features all_full
The binary will be installed in ~/.cargo/bin.
Compiling from source also works similarly:
```bash git clone git@github.com:jqnatividad/qsv.git cd qsv cargo build --release --features all_full
cargo build --release --locked --features all_full ```
The compiled binary will end up in ./target/release/.
To enable optional features, use cargo --features (see Feature Flags for more info):
```bash cargo install qsv --features apply,generate,lua,fetch,foreach,python,self_update,full
cargo install qsv --features all_full
cargo install qsv --features nopython_full
cargo install qsv --features lite
cargo install qsv --features datapusher_plus
cargo build --release --features apply,generate,lua,fetch,foreach,python,self_update,full
cargo build --release --features all_full
cargo build --release --features nopython_full
cargo build --release --features lite
cargo build --release --features datapusher_plus ```
access to a native python interpreter for those platforms (aarch64, i686, and arm) on GitHub's x86_64-based action runners. Compile natively on those platforms with Python 3.6+ development environment installed, if you want to enable the python feature.
qsv's MSRV policy is to require Rust stable - currently version 1.65.
qsv's command-line options are quite extensive. Thankfully, since it uses docopt for CLI processing, we can take advantage of docopt.rs' tab completion support to make it easier to use qsv at the command-line (currently, only bash shell is supported):
```bash
cargo install docopt
echo "DOCOPTWORDLISTBIN=\"$(which docopt-wordlist)"\" >> $HOME/.bashcompletion echo "source \"$(pwd)/scripts/docopt-wordlist.bash\"" >> $HOME/.bashcompletion echo "complete -F docoptwordlistcommands qsv" >> $HOME/.bashcompletion ```
qsv recognizes UTF-8/ASCII encoded, CSV (.csv) and TSV files (.tsv and .tab). CSV files are assumed to have "," (comma) as a delimiter,
and TSV files, "\t" (tab) as a delimiter. The delimiter is a single ascii character that can be set either by the --delimiter command-line option or
with the QSV_DEFAULT_DELIMITER environment variable or automatically detected when QSV_SNIFF_DELIMITER is set.
When using the --output option, note that qsv will UTF-8 encode the file and automatically change the delimiter used in the generated file based on the file extension - i.e. comma for .csv, tab for .tsv and .tab files.
JSONL/NDJSON files are also recognized and converted from/to CSV with the jsonl and tojsonl commands respectively.
The fetch & fetchpost commands also produces JSONL files when its invoked without the --new-column option, and TSV files with the --report option.
The sniff, sortcheck and validate commands produce JSON files with their --json and --pretty-json options.
The schema command produces a JSON Schema Validation (Draft 7) file with the ".schema.json" file extension, which can be used with the validate command.
The excel command recognizes Excel and Open Document Spreadsheet(ODS) files (.xls, .xlsx, .xlsm, .xlsb and .ods files).
qsv validates against the RFC 4180 CSV standard. However IRL, CSV formats vary significantly and qsv is actually not strictly compliant with the specification so it can process "real-world" CSV files. qsv leverages the awesome Rust CSV crate to read/write CSV files.
Click here to find out more about how qsv conforms to the standard using this crate.
The following commands require UTF-8 encoded input (of which ASCII is a subset) - dedup, exclude, fetch, fetchpost, frequency, join, schema, sort, stats & validate.
For these commands, qsv checks if the input is UTF-8 encoded by scanning the first 8k, and will abort if its not unless QSV_SKIPUTF8_CHECK is set. On Linux and macOS, UTF-8 encoding is the default.
This was done to increase performance of these commands, as they make extensive use of from_utf8_unchecked so as not to pay the repetitive utf-8 validation penalty, no matter how small, even for already utf-8 encoded files.
Should you need to re-encode CSV/TSV files, you can use the input command to transcode to UTF-8. It will replace all invalid UTF-8 sequences with �. Alternatively, there are several utilities you can use to do so on Linux/macOS and Windows.
Unlike other modern operating systems, Microsoft Windows' default encoding is UTF16-LE. This will cause problems when redirecting qsv's output to a CSV file and trying to open it with Excel (which ignores the comma delimiter, with everything in the first column):
qsv stats wcp.csv > wcpstats.csv
Which is weird, since you would think Microsoft's own Excel would properly recognize UTF16-LE encoded CSV files. Regardless, to create a properly UTF-8 encoded file, use the --output option instead:
```
qsv stats wcp.csv > wcpstats.csv
qsv stats wcp.csv --output wcpstats.csv ```
With the python feature, qsv will look for Python shared libraries (libpython* on Linux/macOS, python*.dll on Windows) against which it was compiled,
and abort with an error if not found, detailing the Python library it was looking for.
Note that this will happen as soon as the qsv binary is invoked, even if you're not running the py command.
If you don't need to run the py command, simply use qsvnp ("np" stands for "no python"), qsvlite, or qsvdp.
If you need the py command, the prebuilt qsv binary is compiled, as a policy,
using the current stable Python minor version (currently Python 3.11) at the time of release.
If you require a different Python version (Python 3.6 and up are supported), you'll need to install/compile from source, making sure you have the development libraries for the desired Python version installed when doing so.
PyO3 - the underlying crate that enables the python feature, uses a build script to determine the Python version and set the correct linker arguments. By default it uses the python3 executable.
You can override the Python interpreter by setting PYO3_PYTHON (e.g., PYO3_PYTHON=python3.6), before installing/compiling qsv. See the PyO3 User Guide for more information.
If you're distributing python-enabled qsv, you can also "bundle" the Python shared library by including it in the same directory as the qsv binary. qsv will automatically use
the "bundled" library instead of the default Python version in the environment.
Also, consider using the lua/luajit commands instead of the py command if the mapping/filtering operation you're trying to do can be done with lua/luajit. Lua is much faster than Python and LuaJIT is even faster still. In addition, Lua/LuaJIT is embedded into qsv, can do aggregations & has no external dependencies, unlike Python.
The py command cannot do aggregations because PyO3's GIL-bound memory limitations will quickly consume a lot of memory (see issue 449 for details).
To prevent this, the py command processes CSVs in batches (default: 30,000 records), with a GIL pool for each batch, so no globals are available across batches.
| Variable | Description |
| --- | --- |
| QSV_DEFAULT_DELIMITER | single ascii character to use as delimiter. Overrides --delimeter option. Defaults to "," (comma) for CSV files and "\t" (tab) for TSV files when not set. Note that this will also set the delimiter for qsv's output to stdout.
However, using the --output option, regardless of this environment variable, will automatically change the delimiter used in the generated file based on the file extension - i.e. comma for .csv, tab for .tsv and .tab files. |
| QSV_SNIFF_DELIMITER | if set, the delimiter is automatically detected. Overrides QSV_DEFAULT_DELIMITER and --delimiter option. Note that this does not work with stdin. |
| QSV_NO_HEADERS | if set, the first row will NOT be interpreted as headers. Supersedes QSV_TOGGLE_HEADERS. |
| QSV_TOGGLE_HEADERS | if set to 1, toggles header setting - i.e. inverts qsv header behavior, with no headers being the default, and setting --no-headers will actually mean headers will not be ignored. |
| QSV_AUTOINDEX | if set, automatically create an index when none is detected. Also automatically update stale indices. |
| QSV_COMMENT_CHAR | set to an ascii character. If set, any lines(including the header) that start with this character are ignored. |
| QSV_MAX_JOBS | number of jobs to use for multithreaded commands (currently apply, dedup, extsort, frequency, schema, sort, split, stats, tojsonl and validate). If not set, max_jobs is set to the detected number of logical processors. See Multithreading for more info. |
| QSV_NO_UPDATE | if set, prohibit self-update version check for the latest qsv release published on GitHub. |
| QSV_PREFER_DMY | if set, date parsing will use DMY format. Otherwise, use MDY format (used with apply datefmt, schema, sniff & stats commands). |
| QSV_REGEX_UNICODE | if set, makes search, searchset and replace commands unicode-aware. For increased performance, these commands are not unicode-aware by default and will ignore unicode values when matching and will abort when unicode characters are used in the regex. Note that the apply operations regex_replace operation is always unicode-aware. |
| QSV_SKIPUTF8_CHECK | if set, skip UTF-8 encoding check. Otherwise, for several commands that require UTF-8 encoded input (see UTF8-Encoding), qsv scans the first 8k. |
| QSV_RDR_BUFFER_CAPACITY | reader buffer size (default (bytes): 16384) |
| QSV_WTR_BUFFER_CAPACITY | writer buffer size (default (bytes): 65536) |
| QSV_LOG_LEVEL | desired level (default - off; error, warn, info, trace, debug). |
| QSV_LOG_DIR | when logging is enabled, the directory where the log files will be stored. If the specified directory does not exist, qsv will attempt to create it. If not set, the log files are created in the directory where qsv was started. See Logging for more info. |
| QSV_PROGRESSBAR | if set, enable the --progressbar option on the apply, fetch, fetchpost, foreach, lua, py, replace, search, searchset, sortcheck and validate commands. |
| QSV_REDIS_CONNSTR | the fetch command can use Redis to cache responses. Set to connect to the desired Redis instance. (default: redis:127.0.0.1:6379/1). For more info on valid Redis connection string formats, see https://docs.rs/redis/latest/redis/#connection-parameters. |
| QSV_FP_REDIS_CONNSTR | the fetchpost command can also use Redis to cache responses (default: redis:127.0.0.1:6379/2). Note that fetchpost connects to database 2, as opposed to fetch which connects to database 1. |
| QSV_REDIS_MAX_POOL_SIZE | the maximum Redis connection pool size. (default: 20). |
| QSV_REDIS_TTL_SECONDS | set time-to-live of Redis cached values (default (seconds): 2419200 (28 days)). |
| QSV_REDIS_TTL_REFRESH| if set, enables cache hits to refresh TTL of cached values. |
Several dependencies also have environment variables that influence qsv's performance & behavior:
fetch, validate and --update functions and will honor proxy settings set through the HTTP_PROXY, HTTPS_PROXY and NO_PROXY environment variables.ℹ️ NOTE: To get a list of all active qsv-relevant environment variables, run
qsv --envlist. Relevant env vars are defined as anything that starts withQSV_andMIMALLOC_, and the proxy variables listed above.
qsv has several features:
mimalloc (default) - use the mimalloc allocator (see Memory Allocator for more info).apply - enable apply command. This swiss-army knife of CSV transformations is very powerful, but it has a lot of dependencies that increases both compile time and binary size.fetch - enables the fetch and fetchpost commands.generate - enable generate command.full - enable to build qsv binary variant which is feature-capable.all_full - enable to build qsv binary variant with all features enabled (apply,fetch,foreach,generate,luajit,python).nopython_full - enable to build qsvnp binary variant with all features (apply,fetch,foreach,generate,luajit) EXCEPT python.lite - enable to build qsvlite binary variant with all features disabled.datapusher_plus - enable to build qsvdp binary variant - the DataPusher+ optimized qsv binary.nightly - enable to turn on nightly/unstable features in the rand, regex, hashbrown, parking_lot and pyo3 crates when building with Rust nightly/unstable.self_update - enable self-update engine, checking GitHub for the latest release.The following "power-user" features can be abused and present "foot-shooting" scenarios:
lua - enable lua command. Embeds a Lua 5.4 interpreter into qsv.luajit - enable luajit command. Embeds a LuaJIT 2.0 interpreter into qsv. LuaJIT is a Just-In-Time compiler for the Lua 5.1 language and is thus much faster than Lua. Note that the lua and luajit interpreters are mutually exclusive features.foreach - enable foreach command (not valid for Windows).python - enable py command (requires Python 3.6+ shared library). Note that qsv will look for the Python shared library (libpython.* on Linux/macOS, python*.dll on Windows) for the Python version it was compiled against and will abort if the library is not found, even if you're not using the py command. Check Python section for more info.ℹ️ NOTE:
qsvlite, as the name implies, always has non-default features disabled.qsvcan be built with any combination of the above features using the cargo--features&--no-default-featuresflags. The pre-builtqsvbinaries has all applicable features valid for the target platform[^7].
Dual-licensed under MIT or the UNLICENSE.
This project is unrelated to Intel's Quick Sync Video.