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 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. Provide the exact text of each license used, verbatim.
  2. Include a copyright notice and license in (or about) each file.
  3. Provide an inventory for included software.

You are recommended to read the recommendations in full for more details.

This tool exists to facilitate the developer in complying to the above recommendations. It will serve as a linter for compliance, and as a compiler for generating the bill of materials.

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 3.5+
  • Pip
  • python3-pygit2

You can install python3-pygit2 via your operating system’s package manager. For Debian-like GNU/Linux distributions this would be:

apt-get install python3-pygit2

Note that simply installing pygit2 via pip does not work as this omits the libgit2 dependency.

You can also use reuse without python3-pygit2 at the cost of significantly degraded performance as the amount of files to process increases.

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.
    • A special note on the GPL: If you use Valid-License-Identifier: GPL-3.0 or name the file LICENSES/GPL-3.0.txt, this will catch all the following licenses: GPL-3.0, GPL-3.0+, GPL-3.0-only and GPL-3.0-or-later. This applies to the entire GPL family of licenses.
  • Add a comment header to each file that says SPDX-License-Identifier: GPL-3.0-or-later. Replace GPL-3.0-or-later with the license that applies to the file. If you cannot edit the comment header, include a debian/copyright file.
  • Add a comment header to each file that says © YEAR  NAME. You can be flexible with the format, just make sure that the line starts with the copyright sign: ©. You can add multiple lines.

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/curl$ reuse lint

All the listed files have no licence information associated with them.

To generate a bill of materials, use reuse compile:

~/Projects/curll$ reuse compile
SPDXVersion: SPDX-2.1
DataLicense: CC0-1.0
DocumentName: curl
Creator: Person: Anonymous ()
Creator: Organization: Anonymous ()
Creator: Tool: reuse-0.0.4
Created: 2017-11-15T11:42:28Z
CreatorComment: <text>This document was created automatically using available reuse information consistent with the REUSE Initiative.</text>

Ideally, you would distribute this bill of materials together with the tarfile distribution of your project.

Make sure that, when outputting to a file, this file ends in the .spdx extension. If you do not do this, the tool will attempt to include the file itself into the bill of materials, which obviously will not work.



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/
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 Free Software Foundation Europe e.V.

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