I am back porting a bunch of code to run on older kernels. (gcc 4.9 dependencies, x11, vlc etc.) as *.deb files. In this process, ( I am new to packaging) I need to create a copyright file. I can have a blank one, I know, but I would like to know, what is the copyright format?
Do i take the license of the software I am packaging? Or can I give the package a different license than the source licence?
I have been reading: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/ but I am still confused about license and copyright, and whether or not license and copyrights are different for the *.deb file I am making.
Can someone clarify this?
First, according to Debian policy, it's not necessary to use any particular format for the debian/copyright file, as long as the reader can easily tell what copyrights and license terms apply to the package or to individual files (and, of course, as long as those license terms are actually met). I personally appreciate it when a packager uses the copyright-format/1.0, though; it's usually much clearer to read.
The license information in debian/copyright should cover the copyright(s) and licensing of the package you're distributing, as well as any additional copyright and licensing you want to apply to your packaging.
You can't give the package a different license than the source license unless you have permission to do so (nothing gives you automatic permission to license someone else's property on your own terms). Some open source licenses imply that it's ok to redistribute the source or derivatives of the source under a different license, as long as the copyright notice and a disclaimer are kept intact.
It's fairly common, for example, for code licensed under an MIT/X11-style license to be incorporated into code under a BSD-style or GPL license. The resulting combined work is then distributable as long as the terms of both licenses are met (this is not a very onerous requirement in the case of MIT/X11/BSD), and both copyright notices are included. If it's possible to meet the terms of two or more licenses at the same time, we say those licenses are "compatible".
Some works meticulously keep track of what copyrights and licenses apply to each particular file when combining source from multiple origins. Some instead apply all licenses and all copyrights of component parts to the entire combined work. Both are generally accepted by the open source community, as long as it's clear that an effort is being made to identify and comply with the original licenses. Both of those are easily representable in the copyright-format/1.0 syntax.
(I am not a lawyer, this is not legal advice, consult a real lawyer if you are worried about actual legality of relicensing, etc.)