Your knowledge is definitely scant and in fact I think you've been blatantly misinformed. Just because you edit with Emacs, compile with gcc, link against glibc, and debug with gdb absolutely does not require you to put your software under the GPL and absolutely does not require you to give your software away. For the tools (emacs, vi, gcc, etc.), the use of a GPL tool doesn't impact the ownership of anything that you create with that tool. As for libraries, most are released under the LGPL (library/lesser GPL). The basic premise of LGPL is that you can link your code against that library without causing your code to come under the GPL. If you make changes to the library, you have to distribute that code, but it still doesn't require you to release your own code. There may be exceptions, so you should examine each library that you want to use, but most of the big ones (glibc, gtk, gnome, zlib, etc.) are LGPL. The best development tools on linux are the ones that come in every distribution, and nothing prevents you from using them to create commercial software. If you want specific information on what your rights are with the L?GPL, you should go to http://www.gnu.org. That being said, with the exception of niche and vertical markets, linux software is probably not going to make much money for you. The market is small, and there is already so much useful - and free - software that the average linux desktop user just isn't interested in spending money on non-free software. Exceptions are things like vmware, codeweavers crossover, etc., that don't have a high-quality free counterpart.