GNU

[Q-efx]

well, just a question, if something is published under the gnu, and some make changes to a source code ( upgrading for example) this work must be published under the same licence? Or i am wrong?

[rogerborg]

The what? There's no license called "GNU".

If you mean the GPL, then (basically) yes.

It doesn't even have to be modified; if you (re)publish a GPL licensed product, then you must comply with the GPL license, which means licensing it as GPL and making the source available (or referencing where you obtained it from, if you're making a non-commercial distribution).

There are often alternatives though. If you explain what you're trying to do, perhaps we can suggest alternatives.

[Q-efx]

yes i mean the gpu somtimes called gnu, gnu general using

i ask cause i find from time to time software, that were under the gpl extended or modified. And then with a powered by logo, that is in source code commented as "do not remove" .... well this means i could remove it without problems

[Klasker]

I doubt anyone will be suing you, but if the source code says "do not remove," then I suggest you don't remove it. Never heard of GNU General Using -- I think you mean GNU General Public License (GPL) like rogerborg said.

[bitplane]

Someone who states "do not change this code" yet offers the code under the GPL is attempting to restrict your freedom to change the software. If they don't agree with this freedom then they shouldn't have released it under the GPL in the first place. IMO you're free to change it, both ethically and legally.

However, the GPL only applies to programs and their source code, so they might place other restrictions on using their media. Any pictures, sounds, models etc that came with it may have the condition that you display their logo, so by taking out the logo you could be in breach of copyright.