The GPL also allows people to take and modify free software, and distribute their own versions of the software. However, any derived works from GPL software must also be covered by the GPL. In other words, a company could not take Linux, modify it, and sell it under a restrictive license. If any software is derived from Linux, that software must be covered by the GPL as well.

People and organizations can distribute GPL software for a fee and can even make a profit from its sale and distribution. However, in selling GPL software, the distributor can't take those rights away from the purchaser; that is, if you purchase GPL software from some source, you may distribute the software for free or sell it yourself as well.

This might sound like a contradiction at first. Why sell software for profit when the GPL allows anyone to obtain it for free? When a company bundles a large amount of free software on a CD-ROM and distributes it, they need to charge for the overhead of producing and distributing the CD-ROM, and they may even decide to make profit from the sale of the software. This is allowed by the GPL.

Organizations that sell free software must follow certain restrictions set forth in the GPL. First, they can't restrict the rights of users who purchase the software. This means that if you buy a CD-ROM of GPL software, you can copy and distribute that CD-ROM free of charge, or you can resell it yourself. Second, distributors must make it obvious to users that the software is indeed covered by the GPL. Third, distributors must provide, free of charge, the complete source code for the software being distributed, or they must point their customers on demand to where the software can be downloaded. This will allow anyone who purchases GPL software to make modifications of that software.

Allowing a company to distribute and sell free software is a very good thing. Not everyone has access to the Internet to download software, such as Linux, for free. The GPL allows companies to sell and distribute software to those people who do not have free (cost-wise) access to the software. For example, many organizations sell Linux on floppy, tape, or CD-ROM via mail order, and make profit from these sales. The developers of Linux may never see any of this profit; that is the understanding that is reached between the developer and the distributor when software is licensed by the GPL. In other words, Linus knew that companies may wish to sell Linux and that he may not see a penny of the profits from those sales.

In the free software world, the important issue is not money. The goal of free software is always to develop and distribute fantastic software and to allow anyone to obtain and use it. In the next section, we'll discuss how this applies to the development of Linux.

1.5. Software Features		1.7. Open Source and the Philosophy of Linux