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reuse is a tool for compliance with the REUSE Initiative recommendations.

Project description


license version python reuse standard-readme status

reuse is a tool for compliance with the REUSE Initiative recommendations.


Copyright and licensing is difficult, especially when reusing software from different projects that are released under various different licenses. The REUSE Initiative 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 license information to each file
  3. Confirm REUSE compliance

You are recommended to read the recommendations in full for more details. (IMPORTANT: These recommendations are currently out-of-date! See <>.)

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

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


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

  • Python 3.6+
  • Pip

To install reuse, you only need to run the following command:

pip3 install --user fsfe-reuse

After this, make sure that ~/.local/bin is in your $PATH.


First, read the REUSE recommendations. In a nutshell:

  • Include the texts of all used licenses in your project.
  • Add a comment header to each file that says SPDX-License-Identifier: GPL-3.0-or-later.
  • Add a comment header to each file that says SPDX-Copyright: $YEAR $NAME. You can be flexible with the format, just make sure that the line starts with SPDX-Copyright:.

Once you have taken those steps (again, read the actual recommendations for better instructions), you can use this tool to verify whether your project is fully compliant with the REUSE recommendations. To check against the recommendations, use reuse lint:

~/Projects/reuse-tool $ reuse lint
Congratulations! Your project is REUSE compliant :-)



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

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.


Copyright (C) 2017-2019 Free Software Foundation Europe e.V.

Licensed under the GNU General Public License version 3 or later.

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.

0.4.0a1 - 2019-06-04

This release is a major overhaul and refactoring of the tool. Its primary focus is improved usability and speed, as well as adhering to a new version of the spec that is currently in the works.

Please note that this release is incomplete, may contain bugs, and its documentation is lacking and/or simply wrong. It is provided as an early preview.


  • 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-Copyright:. 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 Initiative 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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