How can red hat charge for linux? its Open source under the GNU license. Ant that what open source is about free for any one to download the source code and modify.

So the way things are starting to go will linux always be free? And If not won't that hurt the development of it. Think about it if linux could not be freely downloaded now most people would not try it. And if you had to pay for ever release how offen would you upgrade just to try it out.

Can some one explain how red hat is selling linux under the GNU licenses?

This is the old "free as in beer"/"free as in speech" issue.

The GPL does not say that you have to give away your work for free. Red Hat have the right to charge for pressing CDs, printing manuals, providing technical support, paying programmers to hack on OS projects, and paying dividents to shareholders.

The point of Open Source is that any changes they make to the code have to be published.

It is a good thing that distribution companies (like Red Hat, SuSe, Mandrake, ...) can make a profit selling linux, because it is then in their interest for their product to be good, and so they pay programmers to fix bugs and develop features. The GPL forces them to release the code of these changes, and so the whole community benefits.

Even if you don't want to pay for a distro, most commercial ones offer free downloads, hoping that people will like them enough to show their gratitude and buy a box set, or pay for tech support. And in any case there are many non-commercial distributions (Debian, Slackware, Gentoo, ...) that fund their work through donations.

In answer you speciphic question: Yes, linux will always be free. It is illegal to make changes to GPL code and distribute it without making the source code for those changes avaliable. There is are licenses that allow you to do this, such as the Lesser Gnu Public Licence (LGPL) and the BSD licence.

First, the GNU license does not stipulate that the software must be free of charge. The popular quote passed around is something like "GNU is 'free' as in speech, not 'free' as in beer." What the main portion of the GPL says is that if you distribute software derived from GNU sources that you must provide the source code on request. The reason so many distributions offer freely downloadable versions is because they know that once the source code is out, someone, somewhere can compile a package identical to their own and allow other people to download it from a location other than their corporate site. In fact, it would be perfectly legit for me to download Red Hat's CD images, offer them on my server, and charge people 50 cents to download them. In fact, there are companies that do exactly this (selling bundles" of linux distributions for anywhere from $5 to $10).

So Red Hat can charge whatever it likes for its distribution. The cost help recoup some of the money spent paying programmers to create new utilities or add functionality to their distribution. Most people prefer to think of the charge as an initial support cost. When you buy a boxed set from Red Hat, you get access to their technical support for a certain amount of time. That's where Red Hat is really concentrating its effort: technical support for large installations that need answers "yesterday".

I'd suggest everyone interested in using Linux or open source software licensed under the GPL to read the license fully. I probably don't quite grasp all of it yet either, but it's valuable to know what the basics are. There is absolutely no mention in the license that the software must be available without charge, and that creates some confusion when people hear the word "free".

Quote from above post

"It is illegal to make changes to GPL code and distribute it without making the source code for those changes avaliable."

So If I want the source code for RedHat Enterprise. Can I download the source or can I only get the source if I buy the CDs from Red Hat?

To my understanding, Joe Blow on the street cannot walk up to Red hat and request/demand the source code. You must be the recipient of the GPL-based software to have the right to request its source code. Thus, you would have to acquire it from Red Hat to receive that right. If you downloaded a CD image from some third party, then you have a right to request the source from that third party (the perons(s) you received the product from); not Red Hat itself.