Please check this: "Add the GPLv3 header to the top of each source code file"

[rtek1000]

https://gist.github.com/ometa/286e626520e2eb89964e7d23e88c242f

Copyright 200X My Name

This file is part of Foobar.

Foobar 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.

Foobar 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 Foobar. If not, see http://www.gnu.org/licenses/.