Linux is a KERNEL, NOT AN OPERATING SYSTEM started by Linus Torvalds in 1991 at University of Helsinki in Finland. Linux was at first just a hobby for Linus. Linux is free software.
It just so happened that just when Linux was getting usable, GNU had everything it needed except a kernel. Thus, people started using Linux with GNU to make a completely free UNIX-like operating system called GNU/Linux.
Today Linux and GNU/Linux have come a long way from the early 1990's, although they're still mostly used by geeks.
Free software does NOT mean that you do not have to pay to get it. Free software is a matter of freedom, not price. In order for software to be free, users must be able to run, copy, distribute (with a fee or without a fee), study, change and improve the software.
Do not confuse free software with open source software. Although they are very similar, the philosophy behind them is different. Free software is about ethics and open source software is about being practical.
It's pretty amazing that so many people illegally use proprietary software as if it was free software. Why don't they just use free software and avoid legal issues?
A copyleft free software license. That means that anyone can do anything with something under the GPL except deny others' rights given by them by the GPL. Also the GPL requires that all copyright notices and notices that refer to the GPL stay.
What all computers were before GUIs came about. CLI is an interface that only uses text. Some stupid people and groups (like micro$oft, apple and linspire) try to get rid of CLI taking a lot of power away from users. CLI is still used a lot on UNIX and UNIX-like OSs.
If you want to see what's so great about CLI, use GNUBash on a GNU/Linux system.
One of the two continuations of RedHat 9 after it split into RHEL and Fedora Core in 2003.
Fedora Core is a completely FOSSGNU/Linuxdistro that uses RPM, Yum and a modified Linux and is financially supported by RedHat, Inc. Fedora has a very fast release cycle, producing two or three stable releases a year. As of version 3, all of Fedora Core is rather big, taking up four CDs and a little less than seven GB of hard drive space, although not nearly that much is needed to get a Fedora system up and running. Also as of version 3, the default desktop environment is GNOME but included in the nearly seven GB is also KDE and Xfce.
As of the Fedora Core 4 tests, Fedora is for the x86, x64 and PPC CPU architectures.
The only OSs on my hard drive are different versions of Fedora Core :)