This document provides an overview of the history and development of the Linux operating system. It discusses how Linux originated from earlier operating systems like Unix and was completed using software from the GNU project. Key advantages of Linux mentioned include low cost, stability, performance, flexibility and security. The document also describes the file hierarchy and culture of free software in Linux. It provides examples of commands used in Linux and explains the use of sudo for privilege escalation.

1. 1. Introduction:
1.1 what is Linux?
1.2 Advantages of linux over the other operating system.
1.3 FAT, NTFS, EXT
1.4 Culture of free software.
History
The Unix operating systemwas conceived and implemented by Ken Thompson and Dennis Ritchie (both of AT&T
Bell Laboratories) in 1969 and first released in 1970. Its availability and portability caused it to be widely adopted,
copied and modified by academic institutions and businesses.Its design became influential to authors of other
systems.
In 1983, Richard Stallman started the GNU project with the goal of creating a free UNIX-like operating system.As
part of this work, he wrote the GNU General Public License (GPL). By the early 1990s there was almost enough
available software to create a full operating system. However, the GNU kernel, called Hurd, failed to attract enough
attention from developers leaving GNU incomplete.
Anotherfree operating systemproject, initially released in 1977, was the Berkeley Software Distribution (BSD).
This was developed by UC Berkeley from the 6th edition of Unix from AT&T. Since BSD contained Unix code that
AT&T owned, AT&T filed a lawsuit (USL v. BSDi) in the early 1990s against the University of California. This
strongly limited the development and adoption of BSD.
In 1985, Intel released the 80386, the first x86 microprocessor with 32-bit instruction set and MMU with paging.
In 1986, Maurice J. Bach, of AT&T Bell Labs, published The Design of the UNIX Operating System. This
definitive description principally covered the System V Release 2 kernel, with some new features from Release 3
and BSD.
MINIX, a Unix-like systemintended for academic use,was released by Andrew S. Tanenbaum in 1987. While
source code for the systemwas available, modification and redistribution were restricted. In addition, MINIX's 16-
bit design was not well adapted to the 32-bit features of the increasingly cheap and popular Intel 386 architecture for
personal computers.
These factors and the lack of a widely-adopted, free kernel provided the impetus for Torvalds's starting his project.
He has stated that if either the GNU or 386BSD kernels were available at the time, he likely would not have written
his own
Linux is a Unix-like operating system that was designed to provide personalcomputer users a free or very low-cost
operating systemcomparable to traditional and usually more expensive Unix systems .Linux has a reputation as a
very efficient and fast-performing system. Linux's kernel (the central part of the operating system) was developed
by Linus Torvalds at the University of Helsinki in Finland. To complete the operating system, Torvalds and other
team members made use of systemcomponents developed by members of the Free Software Foundation for the
GNU Project.
1.2 Advantages of Linux (why Linux?)
Low cost:
There is no need to spend time and huge amount money to obtain licenses since Linux and much of it’s software
come with the GNU General Public License. There is no need to worry about any software's that you use in Linux.
Stability:
Linux has high stability compared with otheroperating systems.There is no need to reboot the Linux systemto
maintain performance levels. Rarely it freeze up or slow down. It has a continuous up-times of hundreds of days or
more.

2. Performance:
Linux provides high performance on various networks. It has the ability to handle large numbers of users
simultaneously.
Networking:
Linux provides a strong support for network functionality; client and server systems can be easily set up on any
computer running Linux. It can perform tasks like network backup more faster than other operating systems.
Flexibility:
Linux is very flexible. Linux can be used for high performance server applications, desktop applications, and
embedded systems.You can install only the needed components for a particular use. You can also restrict the use of
specific computers.
Compatibility:
It runs all common Unix software packages and can process all common file formats.
Wider Choice:
There is a large number of Linux distributions which gives you a wider choice. Each organization develop and
support different distribution. You can pick the one you like best; the core function's are the same.
Fast and easy installation:
Linux distributions come with user-friendly installation.
Better use of hard disk:
Linux uses its resources well enough even when the hard disk is almost full.
Multitasking:
Linux is a multitasking operating system. It can handle many things at the same time.
Security:
Linux is one of the most secure operating systems.File ownership and permissions make linux more secure.
Open source:
Linux is an Open source operating systems.You can easily get the source code for linux and edit it to develop your
personal operating system.
Today, Linux is widely used for both basic home and office uses.It is the main operating systemused for high
performance business and in web servers. Linux has made a high impact in this world.
Different Distros:
a) Redhatlinux
b) Open Suse
c) Ubunto
d) Linux Mint
e) Fedora
f) ArchLinux
g) Sabayon
h) Debian
i) Mandriva
j) Puppy Linux
Red Hat Enterprise Linux (RHEL) is a Linux-based operating systemdeveloped by Red Hat and targeted toward
thecommercial market. Red Hat Enterprise Linux is released in server versions for x86, x86-64, Itanium, PowerPC
and IBM System z, and desktop versions for x86 and x86-64. All of Red Hat's official support and training and

3. the Red Hat Certification Programcenter around the Red Hat Enterprise Linux platform. Red Hat Enterprise Linux is
often abbreviated to RHEL, although this is not an official designation.
The first version of Red Hat Enterprise Linux to bear the name originally came onto the market as "Red Hat Linux
Advanced Server". In 2003 Red Hat rebranded Red Hat Linux Advanced Server to "Red Hat Enterprise Linux AS",
and added two more variants, Red Hat Enterprise Linux ES and Red Hat Enterprise Linux WS.
While Red Hat uses strict trademark rules to restrict free re-distribution of their officially supported versions ofRed
Hat Enterprise Linux, Red Hat freely provides the source code for the distribution's software, both for free software
whose license requires such publishing and open source software where this is not mandatory. As a result, several
distributors have created re-branded and/orcommunity-supported re-builds of Red Hat Enterprise Linux that can
legally be made available, without official support from Red Hat.
 Linux File Hierarchy Concepts
FileSystem:
Subdirectories of the root directory Content
/bin Common programs,shared by the system, the system administrator and theusers.
/boot The startup files and the kernel, vmlinuz. In some recent distributionsalso grub data.
Grub is the GRand Unified Boot loader and is an attempt to get rid of the many different boot-
loaders we know today.
/dev Contains references to all theCPU peripheral hardware,which are represented as files with
special properties.
/etc Most important system configuration files arein /etc, this directory contains data similarto those
in the Control Panel in Windows
/home Home directories of the common users.

4. /initrd (on some distributions) Information for booting.Do not remove!
/lib Library files,includesfiles for all kindsof programs needed by the system and the users.
/lost+found Every partition has a lost+found in its upper directory.Files that were saved during
failures arehere.
/misc For miscellaneouspurposes.
/mnt Standard mount point for external filesystems, e.g. a CD-ROM or a digital camera.
/net Standard mount point for entire remote filesystems
/opt Typically contains extra and third party software.
/proc A virtual filesystemcontaininginformation aboutsystemresources.More information
about the meaning of the files in proc is obtained by entering the command man proc in a
terminal window. The fileproc.txt discusses thevirtual filesystemin detail.
/root The administrativeuser's homedirectory. Mind the difference between /, the root directory and
/root, the home directory of the root user.
/sbin Programs for useby the system and the system administrator.
/tmp Temporary spacefor use by the system, cleaned upon reboot, so don't use this for savingany
work!
/usr Programs,libraries,documentation etc. for all user-related programs.
/var Storage for all variablefiles and temporary files created by users,such as logfiles,the mail
queue, the printspooler area, spacefor temporary storage of files downloaded from the
Internet, or to keep an image of a CD before burningit.
1.3 Culture of Free Software:
The free culture movement is a social movement that promotes the freedom to distribute and modify creative
works in the form of free content by using the Internet and otherforms of media.
The movement objects to overly-restrictive copyright laws. Many members of the movement argue that such laws
hinder creativity. They call this system"permission culture".
Creative Commons is a well-known website which was started by Lawrence Lessig. It lists licenses that permit
sharing undervarious conditions,and also offers an online search of various creative-commons-licensed
productions.
The free culture movement, with its ethos of free exchange of ideas, is of a whole with the free software movement.
Richard Stallman, the founder of the GNU project, and free software activist, advocates free sharing of information.
He famously stated that free software means free as in “free speech”.
Absolute Path and Relative Path
Absolute Path:
- Begins with “/”
- Gives complete round map to filelocation.
Eg: /usr/share/doc/abc.html
Relative Path:
- Do not begin with “/”
- Specifies location relativeto current workingdir.
Some basic commands:

5. - Changingdirectories:
$cd(changedirectory)
Syntax: cd <dir name>
Eg: $cd Nepal
$cd – goes to root directory.
$cd ..– goes to previous dir.
- Making new directory
$mkdir – to make new dir
Syntax: $mkdir<dir name>
Eg: $mkdirpokhara - creates directory pokhara.
About sudo
Allows a user with proper permissions to execute a command as the superuseror other user. GNU/Linux
distributions use the “su” model to elevate user priveledges. SU (or Substitute User) is a simple command which
allows you to assume anotheridentity on your pc. It’s most-often use is to become the root or administrative user.
Sudo is a tool that supports allowing users to use their own credentials for privilege escalation. No two pas
swords.No root user. Furthermore, sudo already supports granularity. If Linux distributions used sudo instead of su
by default, you wouldn’t have to give out the root password to anyone who needed to become an administrator
Examples
$su -u hope ls ~hope
List the contents ofthe hope directory as the hope user.