It is an operating system known for being developed as an open-source software meaning that the underlying source code can be used, modified and redistributed commercially and non-commercially under the GNU General Public License (GPL).
It is popularly used for servers primarily for its low cost to set-up being under the GNU GPL.
Is a UNIX-like OS
In June 1971, R ichard M atthew S tallman joined MIT Artificial Intelligence Laboratory as a programmer where he gained popularity with the hacker community and came to be known by his now popular name RMS .
At that time, all the programmers used to share their code freely among each other cutting across various institutions
Richard Matthew Stallman
So the companies developing the code refused to share the code with their clients and began restricting copying and redistribution of their software by copyrighting it.
In response to this trend, Stallman, who believed in the principle that software has to be free always, founded the Free Software Foundation and in 1985, published the GNU Manifesto.
This manifesto outlined his motivation for creating a free OS called GNU, which would be compatible with Unix.
He along with a group of like minded programmers started work in developing the tools needed to make a complete OS
In the same year (1985), a professor by name Andy Tanenbaum wrote a Unix like Operating system from scratch for the Intel i386 platform.
He named it Minix.
In 1989, Stallman released the first program independent GNU General Public Licence now popularly known as GPL or copyleft.
Now the only thing that GNU lacked was a completely free OS kernel
In 1990, A finnish student by name Linus Torvalds studying in the University of Helsinki came into contact with Andy Tanenbaum's OS, Minix.
Linus wanted to upgrade Minix by putting in more features and improvements.
But he was prohibited by Tanenbaum to do so.
Then Linus decided to write his own kernel and released it under GPL.
This kernel is now popularly known as Linux
Tux the penguin: Linux’s Dear Logo
The logo of Linux is a penguin
His cute logo has a very interesting history
Initially no logo was selected for Linux.
History of Tux
Once Linus went to the southern hemisphere on a vacation
There he encountered a penguin
As he tried to pat it, the penguin bit his hand.
This amusing incident led to the selection of a penguin as the logo of Linux sometime later.
“ If you want to travel around the world and be invited to speak at a lot of different places, just write a Unix operating system ”
Linux File System Basics
Linux files are stored in a single rooted, hierarchical file system
Data files are stored in directories (folders)
Directories may be nested as deep as needed
/ etc home usr passwd inittab neale scully marty a b Directories User home directories Data files root
The Current Directory
One directory is designated the current working directory
Use pwd to find out where you are
letter doc/letter ./doc/letter /home/neale/doc/letter / etc home usr passwd inittab neale scully marty a doc Current working directory
Some Special File Names
Some file names are special:
/ The root directory (not to be confused with the root user)
. The current directory
.. The parent (previous) directory
~ My home directory
./a same as a
../jane/x go up one level then look in directory jane for x
/home - all users’ home directories are stored here
/bin , /usr/bin - system commands
/sbin , /usr/sbin - commands used by sysadmins
/etc - all sorts of configuration files
/var - logs, spool directories etc.
/dev - device files
/proc - special system files
pwd - print (display) the working directory
cd < dir> - change the current working directory to dir
ls - list the files in the current working directory
ls -l - list the files in the current working directory in long format
Distribution of Linux
Linux distributions (often called distros for short) consist of a large collection of software applications such as word processors, spreadsheets, media players and database applications built on a Linux kernel.
The top 3 DISTROS
Red hat Fedora 12
Conecal Ubuntu 9.10
Distribution of Linux
Knoppix (first Live CD)
There are 2 types of desktop environment for LINUX. GNOME and KDE
The difference between GNOME and KDE are mainly cosmetic. The main difference is the toolkit used to develop them. KDE was developed using Qt while GNOME was developed using GTK+.
Both are Open Source meaning it can be freely modified and redistributed. Examples of other environments: LXDE, EDE, Mezzo, Etoile, UDE, Sugar, OpenWindows, CDE