What is Linux?
Linux is an open source operating system specifically modeled after Unix. You can get any distribution that suits you, from the bare text console to a full blown graphical desktop of the future, building the entire thing from scratch to a simple graphical installer, free (no price) to expensive enterprise systems. It works on systems from the ever-popular Intel processors all the way to your PS3 and Xbox360!
It's completely free!
What does free mean? In the case of Linux, it doesn't always mean free as in free beer (you don't have to pay money), but it always means free as in freedom (do whatever you want to it).
They typically come as bootable CD's you can download and burn (and for more popular distributions, they'll ship the CD to you if you have bad internet). They are also know to come as network installations (where it's all done through a network connection), bootable USB flash drive, pre-installed on some new computers, etc….
There are many linux ditributions; Ubuntu, Debian, Mandriva, Suse, DSL,… All of these have their own pros and cons.
DSL (Damn Small Linux) for example only needs 16MB RAM, and can fully run in RAM with only 128MB.
Ubuntu needs a bit more of RAM (and ROM) but is really easy-to-use.
There are many others, (as many as there are 'real' linux programmers actually).
Programmers from all over the world can help making it better.
Since it is open source, anyone can edit, since linux programming is not a payed job, anyone can join, and leave. (You can't just become one of the main programmers, but you can always send in your work, maybe they'll be able to use it.)
What is not good about Linux?
- Most people think of it as difficult to use, which is partly true. Ubuntu however is one of the 'easy to use'-distributions. (and so is Fedora, in the humble opinion of Mapar007) (and openSuSE 11.1, in the humble opinion of RandomProductions)
- Installing, however, is not (always) as easy. Thus, a manual is STRONGLY advisable (in the world of Linux, this is typically referred to as "The Internet" or "The Official Website for the Distribution").
Ubuntu (and Xubuntu, Kubuntu, Edubuntu)
Ubuntu is one of the most user friendly and easy to use linux distributions.
If a problem occurs, you will probably find a solution on ubuntuforums.org.
Mostly someone else already had the same problem.
If you can't find any solution, you can still ask it yourself.
Unbuntu can use packages to install programs.
This can be done with a synaptic package manager or apt-get.
Fedora and RedHat
Fedora is, like Ubuntu, a very user friendly distribution. It also supports packages (.rpm files, installed with yum or rpm -i, on the commandline, but mostly a GUI frontend is available too).
As the packages for mandriva Linux are in .rpm format too, some of them (but not all) are compatible with Fedora.
Quick side note: openSuSE, which is similar to Fedora and RedHat, is also a great distribution, and like Fedora and RedHat, also use .rpm packages.
Compiling from C-Source under Linux
This is how it is done in most cases. If scripts listed here are not available, or to be on the safe side, refer to the README and INSTALL text files (yes, they're usually in all caps, without a .txt at the end)
1. Open a terminal window and cd to the source directory.
2. Type ./configure
3. Wait for the script to complete (if any errors, install required packages (listed on stdout)
4. Type make
5. Type sudo make install (or su -c "make install")
In most cases you need to know the password for the root user to install software! (for make install, e.g.)