# Install crf++ with Homebrew Conditional random fields for segmenting/labeling sequential data. Version 0.58 via Homebrew; verified 2026-07-24. ## Install ```sh sudo av install brew:crf++ ``` Additional install commands: ### macOS - Homebrew (100%): ```sh brew install crf++ ``` Evidence: local Homebrew formula metadata ## Package facts - **Package key:** brew:crf++ - **Package manager:** Homebrew - **Package manager page:** - **Version:** 0.58 - **Source summary:** Conditional random fields for segmenting/labeling sequential data - **Homepage:** - **Repository:** - **Upstream docs:** - **License:** LGPL-2.1-only OR BSD-3-Clause - **Source archive:** - **Last updated:** 2026-07-24T20:11:30+09:00 - **Generated:** 2026-08-04T22:13:35+00:00 ## Executables - crf_learn (cli) - crf_test (cli) - crf_learn (alias) - crf_test (alias) ## Install behavior - Post-install hook: not defined - Bottle: available on arm64_big_sur, arm64_linux, arm64_monterey, arm64_sequoia, arm64_sonoma, arm64_tahoe, arm64_ventura, big_sur, catalina, monterey, sonoma, ventura ## Freshness - Page generated: 2026-08-04 - Package-manager version: 0.58 - Package-manager updated: 2026-07-24 - Local data: ok - Upstream repository: https://taku910.github.io/crfpp/ - info: Release/tag comparison is only available for GitHub repositories. ## Project history and usage CRF++ is Taku Kudo's open-source Conditional Random Fields toolkit for segmenting and labeling sequential data. Its official page positions it as a generic-purpose CRF implementation for natural-language-processing tasks such as named entity recognition, information extraction, and text chunking. ### Project history The official CRF++ page lists the first release, version 0.1, on 2005-05-28. The release history shows a steady 2005-2007 development period with API work, parallel training, MIRA training, language bindings, L1 regularization, and a license change to LGPL/BSD dual licensing. ### Adoption history CRF++ became a familiar package for NLP users because it combined a command-line learner and tester, a template-based feature system, and bindings for several languages. Later releases focused on compatibility and maintenance, including GCC, libtool, C++11, Windows, and model-loading fixes. ### How it is used Users prepare training and test files plus feature templates, train models with crf_learn, and decode with crf_test. The package is especially associated with sequence-labeling experiments where researchers want a compact C++ CRF implementation available from source or OS packages. ### Why package nerds care For package maintainers, CRF++ is a classic NLP C++ library/CLI: old enough to need build-system care, small enough to package directly, and still recognizable because many downstream tutorials and research pipelines refer to crf_learn and crf_test. ### Timeline - 2005-05-28: CRF++ 0.1 released - 2006-03-30: Version 0.41 added parallel training - 2006-11-26: Version 0.45 added 1-best MIRA training - 2007-02-12: Version 0.46 changed license to LGPL/BSD dual license and added Perl, Ruby, Python, and Java bindings - 2007-07-07: Version 0.48 added L1-CRF support - 2013-02-13: CRF++ 0.58 released ### Related projects - CRF++ is related to later CRF sequence-labeling packages such as CRFsuite, which explicitly compares its data-format flexibility with CRF++. ### Sources - - ## Security Notes narrow executable package without higher-risk signals. - **Geiger risk:** green / low - narrow executable package without higher-risk signals ## Source Database Details - **Source Database:** Homebrew formula API - **Tap:** homebrew/core - **Full Name:** crf++ - **Version Scheme:** 0 - **Revision:** 0 - **Head Version:** HEAD - **Bottle Stable Root URL:** - **Deprecated:** no - **Disabled:** no - **Keg Only:** no - **URL Keys:** head, stable ## Related links - [Source-control packages](https://pkg.so/source-control-tools/) - Belongs to a source-control command family. - [Terminal utility packages](https://pkg.so/terminal-utilities/) - Matched terminal and command-line workflow metadata. - [Text processing packages](https://pkg.so/text-processing-tools/) - Matched text, document, or structured-data processing metadata. - [Developer build packages](https://pkg.so/developer-build-tools/) - Matched build, compiler, generator, or developer workflow metadata. - [cabocha](https://pkg.so/brew/cabocha/) - Popular package that depends on this formula. - [dvc](https://pkg.so/brew/dvc/) - Shares pkgdb curated category or tags: cli, developer-tools, machine-learning. - [hunspell](https://pkg.so/brew/hunspell/) - Shares pkgdb curated category or tags: cli, developer-tools, nlp. - [scws](https://pkg.so/brew/scws/) - Shares pkgdb curated category or tags: cli, developer-tools, nlp. - [crfsuite](https://pkg.so/brew/crfsuite/) - Shares pkgdb curated category or tags: cli, conditional-random-fields, machine-learning, nlp, sequence-labeling. - [benerator](https://pkg.so/brew/benerator/) - Local metadata places this package in an adjacent workflow. Shared terms: cli, data, developer, developer-tools, test. - [csmith](https://pkg.so/brew/csmith/) - Local metadata places this package in an adjacent workflow. Shared terms: cli, developer, developer-tools, random, test. ## Combined YAML source View the package source record on GitHub. [combined/crf++.yml](https://github.com/mxcl/pkgdb/blob/main/combined/crf++.yml) ## Sources - pkg.so package database - Geiger risk classifier - package-page enrichment - curated package history - package version freshness - pkgdb category and tag curation - package relationship graph - cross-ecosystem install command graph