Just for fun I want to try my hand at sales and marketing. I thought I would take some opensource software, make a few tweaks, slap a new name on it, and sell it. I'm not worried about other people taking my software and doing the same. Are there any licenses that permit this?
You need to read and understand the license. Some licenses permits any changes, some require copyright notification to be displayed, others require you to offer full sourcecode with all your changes (derivative work), a few doesn't permit commercial usage. Failing to comply with the license revokes it, and you need to ask for copyright from the author or stop distributing copies. Some software are covered by multiple licenses so you can choose, or pay off the author for commercial rights. Your idea was novel 20 years ago, but it proved hard to support inherited code and you lose flexibility to design your solutions yourself. Also, ie. slapping your own label on "Open Office" or some such package will both give you support headaches as well as subpar support and erode standardization for your clients. You need to offer something of value, then you can fork or use such software successfully. You might want to open source it yourself, and sell support and commercial licenses, though you often cannot change the original license. By using what most other people use, you'll get a good idea. Ie. Apache license and software is very permissive and used as industry standard. If you do obscure things especially if you're sneaky about it without providing value, it's harder to know what you're allowed to or not, and need to lawyer up.
Again if you could use google: https://en.wikipedia.org/wiki/Comparison_of_free_and_open-source_software_licenses I'm no expert on this but I use GNU v3 for my own stuff (https://github.com/robcarver17/pysystemtrade/blob/master/LICENSE). The summary at the top of the github page is really useful. Notice that with any derivative of a GNU3 project you have to: include the same license and copyright of the original author state the changes you've made (I changed the name) disclose your source code use the same license for your stuff The question is why people would buy something for which you have to release the open source (which is exactly why this license exists - to stop people taking an open source project and monetising it). Maybe if they're too lazy to compile it? As a business this only works if you're providing eg a support package or a paid for enterprise version (like red hat linux). You may find this interesting https://techcrunch.com/2014/02/13/please-dont-tell-me-you-want-to-be-the-next-red-hat/ GAT
I've used open source software in various forms in commercial applications for years. You absolutely have to be careful of licensing. e.g. GPL absolutely sucks in this case. If you use GPL code in your application the license says you're supposed to release the source code of the entire application! GPL is a virus basically. For one project we needed a somewhat obscure open source crypto library that was GPL. By simply asking, I was able to get the author to change his license from GPL to LGPL. LGPL lets you do anything you want. Just do some searching and you'll find that there are active lawsuits right now for open source license violations. Yes, they *are* suing for shenanigans like you're describing.
I did use google, found the sites mentioned, and those sites did not answer the question asked. Still looking. Thanks for the input.
Realize though that this "virus" (or poison pill if you will) is there for a good reason. It's to prevent freeloaders from basically stealing the work of others and never giving back.