6.6.3 License Notices for Code

Typically the license notice for program files (including build scripts, configure files and makefiles) should cite the GPL, like this:

This file is part of GNU package.

GNU package is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

GNU package 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 for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

But in a small program which is just a few files, you can use this instead:

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program 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 for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

In either case, for those few packages which use the Lesser GPL (see Licensing of GNU Packages), insert the word “Lesser” before “General” in all three places. https://www.gnu.org/licenses/gpl-howto.html discusses application the GPL in more detail.