I have a script built in php (which is open source) and i want to heavily modify it (including it's look). I have checked the files and there is no copyright, no license, no legal information... If i create my new script based on the existing one, will i own the copyright for it? If not, can someone prove that they are the rightful owners of this initial script (if yes, how?) I didn't find any help related to copyright of code, especially as it's open source code. Hope anyone can help.
Ask the owner of the script how it is licensed. Open source does not mean it is free to distribute as your own. Given the fact that there is no license, it's quite possible that the owner doesn't care what you do with it. However, I would attempt to try and figure out how it is licensed.
you can modify open source but to redistribute i think u need the script owners permission not totally sure abt that part though
As a bare minium I think you should place something in the comments letting people know that, and where the original come from. Most likely the owner does not care, otherwise he would of added some copyright information.
You should at least give reference to the original author of the code that you use. It just seems like the right thing to do even if no license was applied to it just common courtesy. And when you release the script (if you choose to) make sure to release under the appropriate license.
There are different flavours of open source. If it's a GPL-type licence, then no matter how much you modify it, it will always remain GPL and you have to use the same licence when distributing it. If it's a BSD-type licence, then you can do whatever you want as long as you leave the attribution intact.
I would like to discuss my experience in this point , i am using Cakephp and i make one website using cakephp script and module and i am selling that script since last 1 year...
CakePHP is released under the MIT licence, which is a BSD-style licence. If you are not including a copy of the licence notification with your software then you are in violation.