The main difference is that the AGPL requires you to get a copy of the software source code if you interact with it over the internet. That doesn't mean that th

The main difference is that the AGPL requires you to get a copy of the software source code if you interact with it over the internet. That doesn't mean that the software you use to access it becomes part of a derived work, just that you should have access to it the same way that somebody should have access to it if they had a local copy, where the software is GPL. As for the LGPL, that one was originally made for libraries (Library GPL), but the FSF changed the name, because they don't want to encourage its use in libraries by default - many libraries are indeed LGPL, but others are not. If you want to your program to have the best possible commandline support, as an example, you can use the same library as the bash shell does, but only if your program is GPL.