GPL Licensing – Are These Steps Enough to Put Bash Script Under GPL 3?

You are correct that you should:

• Assert Copyright
• Grant people explicit rights to use, modify and distribute your code.

In many places, the idea of public domain is not recognized. In order for someone to be able to (legally) use your code, there must be something that says that they can, and under what conditions. For snippets, I highly recommend the 3 clause BSD style license. It asserts your copyright, tells people that they are free to do whatever they like with the code, so long as they preserve your copyright when distributing it via source and tells them that they can't use your name to endorse derived works of the code without your permission.

The GPL has very specific definitions of what should happen when you combine GPL covered work with something else. The GPL has to prevail as the dominate license in the code base, which means someone using your snippets inherits the GPL. The LGPL (known as the library GPL, or lesser GPL) is more suited for that, because it allows linking without inheriting the license. Still, if you're going to take the teeth out of the GPL, you might as well use a much simpler license.

Another excellent choice would be the MIT license, which is very similar to the three clause BSD style license.

Finally, if you must use the GPL, please indicate "Version 2 or later" if at all possible. This ensures that your code can work in places where a tree might be using "Version 2 Only", which is quite common. A substantial portion of the Linux kernel specifies version 2 only, GPL3 (while widely accepted) was met with a fair amount of criticism and rejection.

I'm not discounting the importance, significance or usefulness of the GPL. I'm just suggesting that it might not be the best choice for snippets and libraries.

Keep it Simple

Use the MIT/X11 License.

• open and permissible,
• no-brainer / simple,
• allows both free and commercial re-use,
• short,
• clearly gives you copyright,
• well-known and widely used.

I rarely recommend anything else if I don't have a specific reason or am not bound by another license.

Copyright (C)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Or Just Hyper-Link It...

Many JavaScript libraries simply provide:

• a copyright notice,
• and a URL of a publicly hosted verbatim of the license.

This can be an alternative, which allows you to have still a very clear license and keep it short.

IANAL Disclaimer

Though, IANAL and I'm not entirely sure this hyper-link theory really holds, as links are not really perennial resources (though you might argue you could try to prove what they pointed to or contained at a time T).

Laws regulating software, both national or international, are pretty much still in their infancy. This is all rather gray. So you could just go with it, as for now it's a bit obscure what flies and what doesn't.