# cuniq **The pitch**: cuniq is a dedicated command line tool for counting unique lines in text input. If you find yourself frequently running commands like `sort -u | wc -l` or `sort | uniq -c` you will find improved performance by using cuniq instead. **The anti-pitch**: For small inputs you're fine using sort and uniq, as we're talking millisecond-savings by switching to cuniq. However, if you've been using `sort | uniq | wc -l` you should switch to `sort -u | wc -l`, as it's free performance gain without having to go outside standard POSIX commands. ## Performance cuniq has been benchmarked against various combinations of GNU coreutils (sort, uniq, and wc) as well as other hashing-based Rust utilities [runiq](https://crates.io/crates/runiq), [sortuniq](https://crates.io/crates/sortuniq), and [huniq](https://crates.io/crates/huniq). As of this writing, you should not use runiq 2.0.0 or sortuniq 0.2.0 for counting unique lines: they underperform cuniq in all cases, and in many cases their performance is on par with or even worse than `sort -u | wc -l`. For **counting** cuniq reliably outperforms GNU sort in all cases. For **reporting line occurrence counts** cuniq reliably outperforms GNU uniq in all cases except one: > [!NOTE] > If your input has extremely few duplicates and you want a sorted report, than you're better off using `sort | uniq -c`. > This is because with extremely few duplicates both approaches must sort nearly all of the input, but cuniq also wastes > time building a hash table. More data and technical details on the benchmarking and profile-guided optimization that went into creating cuniq are available in [PERFORMANCE.md](PERFORMANCE.md). ## Compatibility cuniq has compatible output with corresponding GNU coreutils commands: | GNU coreutils command | cuniq equivalent | Effect | Notes | |-------------------------|------------------|---------------------------------------|--------------------------------------------------------------| | `sort \| uniq \| wc -l` | `cuniq` | Count of unique lines | | | `sort -u \| wc -l` | `cuniq` | Count of unique lines | this GNU coreutils command is more performant than the above | | `sort \| uniq -c` | `cuniq -c` | Unsorted report of unique line counts | output order differs between the two commands | | `sort \| uniq -c` | `cuniq -cs` | Sorted report of unique line counts | | ## Install ### Installing from Source 1. [Install Rust](https://www.rust-lang.org/tools/install). 2. `RUSTFLAGS="-C target-cpu=native" cargo install cuniq` ### Manual Installation 1. Download cuniq from the [latest release](https://github.com/zkxs/cuniq/releases/latest), and save it to a location of your choice ## Usage cuniq can accept lines from stdin or from a list of files. ``` Usage: cuniq [OPTIONS] [FILES]... Arguments: [FILES]... Files to process Options: -c, --report Instead of printing total unique lines, print a report showing occurrence count of each line. This is only compatible with "exact" mode (the default) -s, --sort Sort report output alphabetically by line. Has no effect unless used with `--report` -t, --trim Remove leading and trailing whitespace from input -l, --lower Convert input to lowercase -m, --mode Sets the algorithm used to count (or estimate) cardinality [default: exact] Possible values: - exact: Uses a hash table to exactly count cardinality. The size of the hash table is proportional to the cardinality of the input. You may use the `--size` flag to set the initial capacity of the internal hash table. For very large inputs `--size` may help reduce expensive hash table reallocations. Avoid setting `--size` for small datasets - near-exact: Uses a hash table to exactly count cardinality, but does not store the original line. This mode is faster than "exact" mode, but hash collision will result in under-counting the cardinality by one. However, hash collisions for a 64-bit hash are exceedingly unlikely. The size of the hash table is proportional to the cardinality of the input. You may use the `--size` flag to set the initial capacity of the internal hash table. For very large inputs `--size` may help reduce expensive hash table reallocations. Avoid setting `--size` for small datasets. This mode is not compatible with `--report` - estimate: Uses the HyperLogLog algorithm to estimate cardinality with fixed memory. Use the `--size` flag to specify the number of 1-byte registers to use. More registers will increase estimate accuracy. By default, 65536 is used. This mode is not compatible with `--report` -n, --size Set the size used by the selected counting mode. See the `--mode` documentation for how this affects each counting mode --threads Set the number of threads used to perform the count. By default, the number of logical cores is used. Not all counting modes support parallelism: see `--mode` for details --no-stdin Disable checking stdin for input. May yield a small performance improvement when only reading input from files --memmap Force reading files via memmap. This may yield improved performance for large files. If the binary was built without memmap support, using this flag will result in an error --no-memmap Disable reading files via memmap, instead falling back to normal reads. By default, cuniq will try to use memmap if it thinks it will be faster. Disabling memmap may yield improved performance for small files -h, --help Print help (see a summary with '-h') -V, --version Print version ``` ## License cuniq is free software: you can redistribute it and/or modify it under the terms of the [GNU General Public License](LICENSE) as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. cuniq is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the [GNU General Public License](LICENSE) for more details. A full list of dependencies is available in [Cargo.toml](cuniq/Cargo.toml), or a breakdown of dependencies by license can be generated with `cargo deny list`.