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reuse is a tool for compliance with the REUSE recommendations.

Project description


The latest version of reuse can be found on PyPI. Information on what versions of Python reuse supports can be found on PyPI. REUSE status readme style standard Packaging status

reuse is a tool for compliance with the REUSE recommendations.


Copyright and licensing is difficult, especially when reusing software from different projects that are released under various different licenses. REUSE was started by the Free Software Foundation Europe (FSFE) to provide a set of recommendations to make licensing your Free Software projects easier. Not only do these recommendations make it easier for you to declare the licenses under which your works are released, but they also make it easier for a computer to understand how your project is licensed.

As a short summary, the recommendations are threefold:

  1. Choose and provide licenses
  2. Add copyright and licensing information to each file
  3. Confirm REUSE compliance

You are recommended to read our tutorial for a step-by-step guide through these three steps. The FAQ covers basic questions about licensing, copyright, and more complex use cases. Advanced users and integrators will find the full specification helpful.

This tool exists to facilitate the developer in complying with the above recommendations.

There are other tools that have a lot more features and functionality surrounding the analysis and inspection of copyright and licenses in software projects. The REUSE helper tool, on the other hand, is solely designed to be a simple tool to assist in compliance with the REUSE recommendations.

Example demo

In this screencast, we are going to follow the tutorial, making the REUSE example repository compliant.

Demo of some basic REUSE tool commands


Installation via package managers

There are packages available for easy install on some operating systems. You are welcome to help us package this tool for more distributions!

An automatically generated list can be found at, without any guarantee for completeness.

Installation via pip

To install reuse, you need to have the following pieces of software on your computer:

  • Python 3.6+
  • pip

You then only need to run the following command:

pip3 install --user reuse

After this, make sure that ~/.local/bin is in your $PATH. On Windows, the required path for your environment may look like %USERPROFILE%\AppData\Roaming\Python\Python39\Scripts, depending on the Python version you have installed.

To update reuse, run this command:

pip3 install --user --upgrade reuse

For full functionality, the following pieces of software are recommended:

  • Git
  • Mercurial 4.3+

Installation from source

You can also install this tool from the source code, but we recommend the methods above for easier and more stable updates. Please make sure the requirements for the installation via pip are present on your machine.

python3 install


First, read the REUSE tutorial. In a nutshell:

  1. Put your licenses in the LICENSES/ directory.
  2. Add a comment header to each file that says SPDX-License-Identifier: GPL-3.0-or-later, and SPDX-FileCopyrightText: $YEAR $NAME. You can be flexible with the format, just make sure that the line starts with SPDX-FileCopyrightText:.
  3. Verify your work using this tool.

Example of header:

# SPDX-FileCopyrightText: 2017 Free Software Foundation Europe e.V. <>
# SPDX-License-Identifier: CC-BY-SA-4.0

To check against the recommendations, use reuse lint:

~/Projects/reuse-tool $ reuse lint

Congratulations! Your project is compliant with version 3.0 of the REUSE Specification :-)

This tool can do various more things, detailed in the documentation. Here a short summary:

  • addheader --- Add copyright and/or licensing information to the header of a file.

  • download --- Download the specified license into the LICENSES/ directory.

  • init --- Set up the project for REUSE compliance.

  • lint --- Verify the project for REUSE compliance.

  • spdx --- Generate an SPDX Document of all files in the project.

  • supported-licenses --- Prints all licenses supported by REUSE.

Run in Docker

The fsfe/reuse Docker image is available on Docker Hub. With it, you can easily include REUSE in CI/CD processes. This way, you can check for REUSE compliance for each build. In our resources for developers you can learn how to integrate the REUSE tool in Drone, Travis, GitHub, or GitLab CI.

You can run the helper tool simply by providing the command you want to run (e.g., lint, spdx). The image's working directory is /data by default. So if you want to lint a project that is in your current working directory, you can mount it on the container's /data directory, and tell the tool to lint. That looks a little like this:

docker run --rm --volume $(pwd):/data fsfe/reuse lint

You can also provide additional arguments, like so:

docker run --rm --volume $(pwd):/data fsfe/reuse --include-submodules spdx -o out.spdx

There are a number of tags available:

  • latest is the most recent stable release.
  • dev follows the master branch of this repository. Up-to-date, but potentially unstable.
  • latest-extra has a few extra packages installed, currently openssh-client.
  • latest-debian is based on python:slim. It is larger, but may be better suited for license compliance.

Run as pre-commit hook

You can automatically run reuse lint on every commit as a pre-commit hook for Git. This uses pre-commit. Once you have it installed, add this to the .pre-commit-config.yaml in your repository:

  - repo:
    rev: latest
      - id: reuse

Then run pre-commit install. Now, every time you commit, reuse lint is run in the background, and will prevent your commit from going through if there was an error.



Any pull requests or suggestions are welcome at or via e-mail to one of the maintainers. General inquiries can be sent to

Interaction within this project is covered by the FSFE's Code of Conduct.

Starting local development is very simple, just execute the following commands:

git clone
cd reuse-tool/
python3 -mvenv venv
source venv/bin/activate
make develop

You need to run make develop at least once to set up the virtualenv.

Next, run make help to see the available interactions.


This work is licensed under multiple licences. Because keeping this section up-to-date is challenging, here is a brief summary as of April 2020:

  • All original source code is licensed under GPL-3.0-or-later.
  • All documentation is licensed under CC-BY-SA-4.0.
  • Some configuration and data files are licensed under CC0-1.0.
  • Some code borrowed from spdx/tool-python is licensed under Apache-2.0.

For more accurate information, check the individual files.

Change log

This change log follows the Keep a Changelog spec. Every release contains the following sections:

  • Added for new features.
  • Changed for changes in existing functionality.
  • Deprecated for soon-to-be removed features.
  • Removed for now removed features.
  • Fixed for any bug fixes.
  • Security in case of vulnerabilities.

The versions follow semantic versioning.

0.14.0 - 2021-12-27

Happy holidays! This is mainly a maintenance release fixing some subcommands and adding loads of supported file types and file names. However, you can also enjoy the supported-licenses subcommand and the --quiet flag for linting as well as better suggestions for license identifiers. Thanks to everyone who contributed!


  • supported-licenses command that lists all licenses supported by REUSE (#401)

  • --quiet switch to the lint command (#402)

  • Better suggestions for faulty SPDX license identifiers in download and init (#416)

  • Python 3.10 support declared

  • More file types are recognised:

    • Apache FreeMarker Template Language (.ftl)
    • AsciiDoc (.adoc, .asc, .asciidoc)
    • Bibliography (.csl)
    • C++ (.cc and .hh)
    • GraphQL (.graphql)
    • Handlebars (.hbs)
    • Markdown-linter config (.mdlrc)
    • MS Office (.doc, .xls, .pptx and many more)
    • Nimble (.nim.cfg, .nimble)
    • Open Document Format (.odt, .ods, .fodp and many more)
    • Perl plain old documentation (.pod)
    • Portable document format (.pdf)
    • Protobuf files (.proto)
    • Soy templates (.soy)
    • SuperCollider (.sc, .scsyndef)
    • Turtle/RDF (.ttl)
    • V-Lang (.v, .vsh)
    • Vue.js (.vue)
  • More file names are recognised:

    • Doxygen (Doxyfile)
    • ESLint (.eslintignore and .eslintrc)
    • Meson options file (meson_options.txt)
    • NPM ignore (.npmignore)
    • Podman container files (Containerfile)
    • SuperCollider (archive.sctxar)
    • Yarn package manager (.yarn.lock and .yarnrc)


  • Updated SPDX license list to 3.15


  • Fix Extensible Stylesheet Language (.xsl) to use HTML comment syntax

  • Allow creating .license file for write-protected files (#347) (#418)

  • Do not break XML files special first line (#378)

  • Make download subcommand work correctly outside of project root and with --root (#430)

0.13.0 - 2021-06-11


  • addheader recognises file types that specifically require .license files instead of headers using UncommentableCommentStyle. (#189)

  • .hgtags is ignored. (#227)

  • spdx-symbol added to possible copyright styles. (#350)

  • addheader ignores case when matching file extensions and names. (#359)

  • Provide latest-debian as Docker Hub tag, created by Dockerfile-debian. (#321)

  • More file types are recognised:

    • Javascript modules (.mjs)
    • Jupyter Notebook (.ipynb)
    • Scalable Vector Graphics (.svg)
    • JSON (.json)
    • Comma-separated values (.csv)
    • Racket (.rkt)
    • Org-mode (.org)
    • LaTeX package files (.sty)
    • devicetree (.dts, .dtsi)
    • Bitbake (.bb, .bbappend, .bbclass)
    • XML schemas (.xsd)
    • OpenSCAD (.scad)
  • More file names are recognised:

    • Bash configuration (.bashrc)
    • (.coveragerc)
    • Jenkins (Jenkinsfile)
    • SonarScanner (
    • Gradle (, gradlew)


  • Bump alpine Docker base image to 3.13. (#369)


  • Fixed a regression where unused licenses were not at all detected. (#285)

  • Declared dependency on python-debian != 0.1.39 on Windows. This version does not import on Windows. (#310)

  • is now recognised instead of the incorrect by addheader. (#306)

  • addheader now checks whether a file is both readable and writeable instead of only writeable. (#241)

  • addheader now preserves line endings. (#308)

  • download does no longer fail when both --output and --all are used. (#326)

  • Catch erroneous SPDX expressions. (#331)

  • Updated SPDX license list to 3.13.

0.12.1 - 2020-12-17


  • Bumped versions of requirements. (#288)

0.12.0 - 2020-12-16

This release was delayed due to the absence of the lead developer (Carmen, me, the person writing these release notes). Many thanks to Max Mehl for coordinating the project in my absence. Many thanks also to the contributors who sent in pull requests, in reverse chronological order: Olaf Meeuwissen, Mikko Piuola, Wolfgang Traylor, Paul Spooren, Robert Cohn, ethulhu, pukkamustard, and Diego Elio Pettenò.


  • Separate Docker image with additional executables installed (fsfe/reuse:latest-extra) (#238)

  • Allow different styles of copyright lines: SPDX (default), String, String (C), String ©, and © (#248)

  • Convenience function to update resources (SPDX license list and exceptions) (#268)

  • More file types are recognised:

    • ClojureScript (.cljc, .cljs)
    • Fortran (.F, .F90, .f90, .f95, .f03, .f, .for)
    • Makefile (.mk)
    • PlantUML (.iuml, .plantuml, .pu, .puml)
    • R (.R, .Renviron, .Rprofile)
    • ReStructured Text (.rst)
    • RMarkdown (.Rmd)
    • Scheme (.scm)
    • TypeScript (.ts)
    • TypeScript JSX (.tsx)
    • Windows Batch (.bat)
  • More file names are recognised:

    • .dockerignore
    • Gemfile
    • go.mod
    • Rakefile


  • Use UTF-8 explicitly when reading files (#242)


  • Updated license list to 3.11.

0.11.1 - 2020-06-08


  • Similar to CAL-1.0 and CAL-1.0-Combined-Work-Exception, SHL-2.1 is now ignored because it contains an SPDX tag within itself.

0.11.0 - 2020-05-25


  • Added --skip-unrecognised flag to addheader in order to skip files with unrecognised comment styles instead of aborting without processing any file.


  • Always write the output files encoded in UTF-8, explicitly. This is already the default on most Unix systems, but it was not on Windows.

  • All symlinks and 0-sized files in projects are now ignored.


  • The licenses CAL-1.0 and CAL-1.0-Combined-Work-Exception contain an SPDX tag within themselves. Files that are named after these licenses are now ignored.

  • Fixed a bug where addheader wouldn't properly apply the template on .license files if the .license file was non-empty, but did not contain valid SPDX tags.

0.10.1 - 2020-05-14


  • Updated license list to 3.8-106-g4cfec76.

0.10.0 - 2020-04-24


  • Add support for autoconf comment style (listed as m4).

  • More file types are recognised:

    • Cython (.pyx, .pxd)
    • Sass and SCSS (.sass, .scss)
    • XSL (.xsl)
    • Mailmap (.mailmap)
  • Added --single-line and --multi-line flags to addheader. These flags force a certain comment style.


  • The Docker image has an entrypoint now. In effect, this means running:

    docker run -v $(pwd):/data fsfe/reuse lint

    instead of

    docker run -v $(pwd):/data fsfe/reuse reuse lint.

0.9.0 - 2020-04-21


  • Added support for Mercurial 4.3+.

  • A pre-commit hook has been added.

  • When an incorrect SPDX identifier is forwarded to download or init, the tool now suggests what you might have meant.


  • Under the hood, a lot of code that has to do with Git and Mercurial was moved into its own module.

  • The Docker image has been changed such that it now automagically runs reuse lint on the /data directory unless something else is specified by the user.


  • Fixed a bug with addheader --explicit-license that would result in file.license.license if file.license already existed.

  • Fixed a Windows-only bug to do with calling subprocesses.

  • Fixed a rare bug that would trigger when a directory is both ignored and contains a .git file.

0.8.1 - 2020-02-22


  • Support Jinja (Jinja2) comment style.

  • Support all multi-line comment endings when parsing for SPDX information.


  • Improvements to German translation by Thomas Doczkal.

  • No longer remove newlines at the end of files when using addheader.

  • There can now be a tab as whitespace after SPDX-License-Identifier and SPDX-FileCopyrightText.

0.8.0 - 2020-01-20


  • Implemented --root argument to specify the root of the project without heuristics.

  • The linter will complain about licenses without file extensions.

  • Deprecated licenses are now recognised. lint will complain about deprecated licenses.

  • ProjectReport generation (lint, spdx) now uses Python multiprocessing, more commonly called multi-threading outside of Python. This has a significant speedup of approximately 300% in testing. Because of overhead, performance increase is not exactly linear.

  • For setups where multiprocessing is unsupported or unwanted, --no-multiprocessing is added as flag.

  • addheader now recognises many more extensions. Too many to list here.

  • addheader now also recognises full filenames such as Makefile and .gitignore.

  • Added BibTex comment style.

  • Updated translations:

    • Dutch (André Ockers, Carmen Bianca Bakker)
    • French (OliBug, Vincent Lequertier)
    • Galician (pd)
    • German (Max Mehl)
    • Esperanto (Carmen Bianca Bakker)
    • Portuguese (José Vieira)
    • Spanish (Roberto Bauglir)
    • Turkish (T. E. Kalayci)


  • The linter output has been very slightly re-ordered to be more internally consistent.

  • reuse --version now prints a version with a Git hash on development versions. Towards that end, the tool now depends on setuptools-scm during setup. It is not a runtime dependency.


  • lint no longer accepts path arguments. Where previously one could do reuse lint SUBDIRECTORY, this is no longer possible. When linting, you must always lint the entire project. To change the project's root, use --root.

  • FileReportInfo has been removed. FileReport is used instead.


  • A license that does not have a file extension, but whose full name is a valid SPDX License Identifier, is now correctly identified as such. The linter will complain about them, however.

  • If the linter detects a license as being a bad license, that license can now also be detected as being missing.

  • Performance of project.all_files() has been improved by quite a lot.

  • Files with CRLF line endings are now better supported.

0.7.0 - 2019-11-28


  • The program's package name on PyPI has been changed from fsfe-reuse to reuse. fsfe-reuse==1.0.0 has been created as an alias that depends on reuse. fsfe-reuse will not receive any more updates, but will still host the old versions.

  • For users of fsfe-reuse, this means:

    • If you depend on fsfe-reuse or fsfe-reuse>=0.X.Y in your requirements.txt, you will get the latest version of reuse when you install fsfe-reuse. You may like to change the name to reuse explicitly, but this is not strictly necessary.

    • If you depend on fsfe-reuse==0.X.Y, then you will keep getting that version. When you bump the version you depend on, you will need to change the name to reuse.

    • If you depend on fsfe-reuse>=0.X.Y<1.0.0, then 0.6.0 will be the latest version you receive. In order to get a later version, you will need to change the name to reuse.

0.6.0 - 2019-11-19


  • --include-submodules is added to also include submodules when linting et cetera.

  • addheader now also recognises the following extensions:

    • .kt
    • .xml
    • .yaml
    • .yml


  • Made the workaround for MachineReadableFormatError introduced in 0.5.2 more generic.

  • Improved shebang detection in addheader.

  • For addheader, the SPDX comment block now need not be the first thing in the file. It will find the SPDX comment block and deal with it in-place.

  • Git submodules are now ignored by default.

  • addheader --explicit-license now no longer breaks on unsupported filetypes.

0.5.2 - 2019-10-27


  • python3 -m reuse now works.


  • Updated license list to 3.6-2-g2a14810.


  • Performance of reuse lint improved by at least a factor of 2. It no longer does any checksums on files behind the scenes.

  • Also handle MachineReadableFormatError when parsing DEP5 files. Tries to import that error. If the import is unsuccessful, it is handled.

0.5.1 - 2019-10-24 [YANKED]

This release was replaced by 0.5.2 due to importing MachineReadableFormatError, which is not a backwards-compatible change.

0.5.0 - 2019-08-29


  • TeX and ML comment styles added.

  • Added --year and --exclude-year to reuse addheader.

  • Added --template to reuse addheader.

  • Added --explicit-license to reuse addheader.

  • binaryornot added as new dependency.

  • Greatly improved the usage documentation.


  • reuse addheader now automatically adds the current year to the copyright notice.

  • reuse addheader preserves the original header below the new header if it did not contain any SPDX information.

  • reuse addheader now correctly handles .license files.

  • Bad licenses are no longer resolved to LicenseRef-Unknown<n>. They are instead resolved to the stem of the path. This reduces the magic in the code base.

  • .gitkeep files are now ignored by the tool.

  • Changed Lisp's comment character from ';;' to ';'.

0.4.1 - 2019-08-07


  • --all argument help to reuse download, which downloads all detected missing licenses.


  • When using reuse addheader on a file that contains a shebang, the shebang is preserved.

  • Copyright lines in reuse spdx are now sorted.

  • Some publicly visible TODOs were patched away.

0.4.0 - 2019-08-07

This release is a major overhaul and refactoring of the tool. Its primary focus is improved usability and speed, as well as adhering to version 3.0 of the REUSE Specification.


  • reuse addheader has been added as a way to automatically add copyright statements and license identifiers to the headers of files. It is currently not complete.

  • reuse init has been added as a way to initialise a REUSE project. Its functionality is currently scarce, but should improve in the future.


  • reuse lint now provides a helpful summary instead of merely spitting out non-compliant files.

  • reuse compile is now reuse spdx.

  • In addition to Copyright and ©, copyright lines can be marked with the tag SPDX-FileCopyrightText:. This is the new recommended default.

  • Project no longer depends on pygit2.

  • The list of SPDX licenses has been updated.

  • Valid-License-Identifier is no longer used, and licenses and exceptions can now only live inside of the LICENSES/ directory.


  • Removed --ignore-debian.

  • Removed --spdx-mandatory, --copyright-mandatory, --ignore-missing arguments from reuse lint.

  • Remove reuse license.

  • GPL-3.0 and GPL-3.0+ (and all other similar GPL licenses) are no longer detected as SPDX identifiers. Use GPL-3.0-only and GPL-3.0-or-later instead.


  • Scanning a Git directory is a lot faster now.

  • Scanning binary files is a lot faster now.

0.3.4 - 2019-04-15

This release should be a short-lived one. A new (slightly backwards-incompatible) version is in the works.


  • Copyrights can now start with © in addition to Copyright. The former is now recommended, but they are functionally similar.


0.3.3 - 2018-07-15


  • Any files with the suffix .spdx are no longer considered licenses.

0.3.2 - 2018-07-15


  • The documentation now builds under Python 3.7.

0.3.1 - 2018-07-14


  • When using reuse from a child directory using pygit2, correctly find the root.

0.3.0 - 2018-05-16


  • The output of reuse compile is now deterministic. The files, copyright lines and SPDX expressions are sorted alphabetically.


  • When a GPL license could not be found, the correct -only or -or-later extension is now used in the warning message, rather than a bare GPL-3.0.
  • If you have a license listed as SPDX-Valid-License: GPL-3.0-or-later, this now correctly matches corresponding SPDX identifiers. Still it is recommended to use SPDX-Valid-License: GPL-3.0 instead.

0.2.0 - 2018-04-17


  • Internationalisation support added. Initial support for:
    • English.
    • Dutch.
    • Esperanto.
    • Spanish.


  • The license list of SPDX 3.0 has deprecated GPL-3.0 and GPL-3.0+ et al in favour of GPL-3.0-only and GPL-3.0-or-later. The program has been amended to accommodate sufficiently for those licenses.


  • Project.reuse_info_of now extracts, combines and returns information both from the file itself and from debian/copyright.
  • ReuseInfo now holds sets instead of lists.
    • As a result of this, ReuseInfo will not hold duplicates of copyright lines or SPDX expressions.
  • click removed as dependency. Good old argparse from the library is used instead.

0.1.1 - 2017-12-14


  • The reuse --help text has been tidied up a little bit.


  • Release date in change log fixed.
  • The PyPI homepage now gets reStructuredText instead of Markdown.

0.1.0 - 2017-12-14


  • Successfully parse old-style C and HTML comments now.
  • Added reuse compile, which creates an SPDX bill of materials.
  • Added --ignore-missing to reuse lint.
  • Allow to specify multiple paths to reuse lint.
  • chardet added as dependency.
  • pygit2 added as soft dependency. reuse remains usable without it, but the performance with pygit2 is significantly better. Because pygit2 has a non-Python dependency (libgit2), it must be installed independently by the user. In the future, when reuse is packaged natively, this will not be an issue.


  • Updated to version 2.0 of the REUSE recommendations. The most important change is that License-Filename is no longer used. Instead, the filename is deducted from SPDX-License-Identifier. This change is NOT backwards compatible.
  • The conditions for linting have changed. A file is now non-compliant when:
    • The license associated with the file could not be found.
    • There is no SPDX expression associated with the file.
    • There is no copyright notice associated with the file.
  • Only read the first 4 KiB (by default) from code files rather than the entire file when searching for SPDX tags. This speeds up the tool a bit.
  • Project.reuse_info_of no longer raises an exception. Instead, it returns an empty ReuseInfo object when no reuse information is found.
  • Logging is a lot prettier now. Only output entries from the reuse module.


  • reuse --ignore-debian compile now works as expected.
  • The tool no longer breaks when reading a file that has a non-UTF-8 encoding. Instead, chardet is used to detect the encoding before reading the file. If a file still has errors during decoding, those errors are silently ignored and replaced.

0.0.4 - 2017-11-06


  • Removed dependency on os.PathLike so that Python 3.5 is actually supported

0.0.3 - 2017-11-06


  • Fixed the link to PyPI in the README.

0.0.2 - 2017-11-03

This is a very early development release aimed at distributing the program as soon as possible. Because this is the first release, the changelog is a little empty beyond "created the program".

The program can do roughly the following:

  • Detect the license of a given file through one of three methods (in order of precedence):
    • Information embedded in the .license file.
    • Information embedded in its header.
    • Information from the global debian/copyright file.
  • Find and report all files in a project tree of which the license could not be found.
  • Ignore files ignored by Git.
  • Do some logging into STDERR.

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