Putting license in each code file? [closed]

A single one outside the code, please! I don't know about the others, but I hate seeing the same thing on top of every file.

I think I've read it a few times, just by page_down-ing through it.

EULA is the wrong term here, as the people looking at source code usually are not end users.

Legally, it makes no difference either; copyright does not need to be declared explicitly.

Basically, all you achieve is a lower risk of people accidentally violating your license terms. You'll have to decide how important that is to you.

I'd say the best compromise is to put a very short header containing a link (absolute URL as well as relative within the project) to the full license text into each source code file. That way, anyone who cares about the license knows where to find it (ideally, people who're willing to pay massive license fees; you certainly want those people to be able to contact you!)

No, you don't have to put the license in each source code file.

If you look closer, most FOSS applications don't do that either. They put a copyright statement at the top of each file and a short sentence telling you what license the file is under and where you can find the full text of the license. They usually point you to the COPYING or LICENSE file containing the full text of the license and/or to a website that contains the full text (in case the COPYING file isn't there anymore).

Like Michael Borgwardt said in his answers, legally you don't have to do this. But it is advisable for source code that you intend to distribute since people can immediately see who has the copyright and what the license is.

It might depend on the license. The GPL distinguishes between preamble and license. It clearly states, that the (annoying) preamble must be part of the code:

Can I omit the preamble of the GPL, or the instructions for how to use it on your own programs, to save space?

The preamble and instructions are integral parts of the GNU GPL and may not be omitted. In fact, the GPL is copyrighted, and its license permits only verbatim copying of the entire GPL. (You can use the legal terms to make another license but it won't be the GNU GPL.) (1)

Source: 1) http://www.gnu.org/licenses/gpl-faq.html#GPLOmitPreamble

See also http://softwarefreedom.org/resources/2012/ManagingCopyrightInformation.html

A free ebook from ifrOSS explains and comments the GPL 2 in german language. There is another one for GPL 3

For a well founded answer you should ask for a legal advice which is not available on sx. If you can not find a lawyer for your (open source) project, have a look at the FSFE legal network.