Is Mac OS X Unix-Based Operating System..?

QueeenZ wrote:
And i know that there are not file extensions in Unix but i know there is in Mac OS.. hmm.. don't get that.. 😀 Because as we all know Bill Gates invented them..

Are you really a unix user? Extensions in unix were around before Bill Gates existed.
Do you have a real question?

Unix does not use file extensions. To say that there are none is a stretch. Certain programs have always used extensions to distinguish various files -- like the C-compilers using .c and .h. But to the system, the extension is just part of the file name with no special significance. Mac OS X applications and services can optionally use extensions to identify file types. There is nothing mysterious about that. To Unix, still, it is just part of the file name.

And i know that there are not file extensions in Unix but i know there is in Mac OS.

Of course there are file extensions in Unix. ,h files, .c files, ...

QueeenZ wrote:
well i figured this out when i tried to go to /usr directory which is knows unix systems dir.. but it's hidden in Mac OS as i see.. 🙂

"Go" menu --> "Go to Folder" --> /usr

See if this helps:

http://en.wikipedia.org/wiki/MacOSX

Mac OS X is Unix based. Some would argue it isn't Unix because it is more based on BSD Unix, and the Mach kernel. System 1 through 9.2.2 have less of a Unix base, but still having some. See these articles:
http://en.wikipedia.org/wiki/Macosx
http://en.wikipedia.org/wiki/OS-9

Mac OS X 10.5 for Intel-based Macs has received UNIX 03 certification so it's about as UNIX as things get nowadays. (10.5 on PPC systems should also pass were Apple to apply for certification, but doubtless they just aren't interested in going to the expense and effort for a discontinued platform).

QueeenZ wrote:
well i figured this out when i tried to go to /usr directory which is knows unix systems dir.. but it's hidden in Mac OS as i see.. 🙂

No, it's not really hidden, it's only hidden in the GUI.
Open a terminal and you will see a complete Unix OS, with Apache servers, PHP, Perl, Python, C, Cpp, AWK, multiple shells, and whatever.
If you are at home in a Unix environment, you will be at home in a terminal.

Some of Mac OS X's assignment of extensions is more for making things obvious what they are. .app applications are really package applications that contain bundled files in a single file. Extensions themselves can be added to files or not, depending on whom you are communicating with. There is a Unix board for discussing Unix attributes of Mac OS X:

http://discussions.apple.com/forum.jspa?forumID=735

And http://www.sourceforge.net/ discusses many open source solutions for Mac OS X that are portable applicatiosn across Unix operating systems.

Start with
http://developer.apple.com/documentation/MacOSX/Conceptual/BPFileSystem/BPFileSy stem.html
http://developer.apple.com/documentation/MacOSX/Conceptual/BPFileSystem/Articles /Domains.html and
http://developer.apple.com/documentation/Performance/Conceptual/FileSystem/FileS ystem.html
All will be revealed.

Jeffrey Jones2 wrote:
Unix does not use file extensions. To say that there are none is a stretch.

I would say that Unix does not need file extensions but it has them in many cases.
In the PC world (and maybe elsewhere), extensions are the scorecards that let you tell the players apart 🙂

In Unix the extensions are a convenient way for humans to know what the file is or does, so when opening a file, one has an idea what tool to use. When 'lessing' a binary file for instance, a warning pops up about the file being binary.
And conversely, in Unix, any file can be run, even a nonsense text file, with sometimes curious results, but the extensions are handy, especially for humans.
Since everything is a file in Unix, so to speak, a directory can have a .txt extension if one so desires.

We are also drifting miles away from the OP's subject, which has been answered several times:
Yes, Leopard is a *nix-based OS.

Message was edited by: nerowolfe

At the risk of prolonging a pointless argument, some Unix users use extensions, some Unix programs use extensions, but they mean nothing at all to the system itself.

Mac OS X is based on the Mach micro kernel and BSD 4.4 (and FreeBSD 5 and onwards for the newest versions, although code from NetBSD has made its way into the BSD subsystem too) and is to be considered a version of Unix. It doesn't sport a typical monolithic kernel like Unix usually does, but as mentioned earlier its kernel is rather a hybrid between two architectures.

Because of the BSD underpinnings, and often relatively simple recompiling efforts, Mac OS X is capable of running a significant number of traditional Unix and open source applications as well as Mac OS X applications. Simultaneously.

Mac OS 9, on the other hand, has no Unix heritage and is not to be mistaken for the real time Unix like operating system, that is OS-9. The makers of OS-9, Microware Systems Corporation, even sued Apple over the name 'OS 9', seemingly thinking that people would mistakenly associate the two products with another.

Mac OS 9 was a cooperatively multitasking, multithreaded single user system, whereas Mac OS X is a multithreaded, multitasking multi user system.

As mentioned by others, Mac OS X 10.5 is certified Unix.