unix - linux what are they?

hi
i will like to know what exactly is unix and linux.
because i see on some hosting websites:
1.unix\linux based system
2.unix based system
3.linux based system

help, i am going insane

thank you

In short: linux!=unix.

I think that about 30 % of the code used in Linux derives from Unix. And Linux is Linus Torvalds's 'free version' of Unix. There are lots of different flavours of both Unix and Linux. And I'll bet that most of the Linux related sites can tell you more about the diffrencies...

//NoXcuz

Unix is a sort of quite similar commercial (and expensive) OSs.

Linux is a system kernel that is similar to Unix kernels. However, it's free (GPLed). The name is also used to describe a combination of the Linux kernel and the GNU tools along with X and other programs, which effectively is a complete OS.

Usually you won't have to worry about that, unless you've got something in your homepage that depends on an OS (very rare).

I assume you come to this post with experience of Microsoft Windows or Apple MacOS, since they are the only two big Operating Systems you could use and not know of GNU/Linux (as Linux is properly known) or UNIX in general.

GNU/Linux is an Operating System, like Windows or MacOS. In structure it is based on the UNIX structure, hence the two terms are kind of interchangeable. UNIX is a family of Operating Systems used for servers and other techy behind-the-scenes computer work, is old, often quite slow, and proprietary. Whic brings me to a summary of what makes GNU/Linux good:

* GNU/Linux is Free Software, meaning you can download it for free, and you are free to use it as you wish (through getting the source code you can copy, modify and redistribute the code).

* GNU/Linux is fast and stable, making it a joy to work with and very weel suited to web hosting (unlike Windows which is slow and unstable in comparison)

* GNU/Linux has a great community behind it, meaning it progresses at astonishing rates and you can continuously upgrade your system at no cost and with few worries.

The only down-side is that, comapred with Windows or MacOS, it is more difficult to install and use. Though that is changing as distributions of GNU/Linux improve.

For more info on GNU/Linux, see:
http://www.gnu.org/gnu/linux-and-gnu.html

For good reviews of different GNU/Linux distributions see:
http://www.thedukeofurl.org