Download What is GNU/Linux?

Welcome to Linux
Community
What is GNU/Linux?
A free Unix-type operating system developed
under the GNU General Public License.
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Open source
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Popular
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Support most of the platforms available
A Short History of UNIX


Multics, AT&T Bell Lab, GE, MIT
1969, UNIX, Ken Thompson, Dennis
Ritchie
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1973, Rewrite UNIX with C
Berkeley UNIX(BSD UNIX)
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Commercial products

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SunOS, Solaris, HP-UX, AIX, SCO UNIX
A Short History of Linux
A Short History of Linux(2)
Brief History of GNU/Linux
•
1985 Free Software Foundation (FSF) founded by Richard
Stallman. Along with other programmers creates the tools
needed to make a UNIX compatible OS
•
1985 Professor Andy Tannenbaum creates a UNIX like operating
system based on System V Unix for the IBM PC & PC/AT
computers. It is called Minix.
•
1989 Richard Stallman releases GPL and GNU software but
lacks a free kernel.
•
1991 Building on the concepts in Minix, Linus Torvalds (Finnish
college student) develops Linux along with help from other
users on the web.
Linux Overview
6
Is Linux difficult ?
This may be true. But the real question is:
do you really want to learn it?
What Linux is
 Strictly speaking Linux refers to the kernel
 GNU/Linux more accurately describes the Operating System. Linux
Kernel combined with GNU utilities and libraries
 Distribution – GNU/Linux bundled with other applications. Examples
Red Hat Linux, Debian, Ubuntu, Suse, Knoppix, etc.
 Distributions can be compiled and maintained by an individual or
corporation. Can be small (single floppy disk) or span several
CD/DVDs.
Linux Overview
8
Open Source Software
 Open Source Software (OSS) generally refers to software for which the source code is available
and which the licensing scheme permits the user to modify it and redistribute it in modified or
unmodified form.
GNU copyleft1
 Nobody should be restricted by the software they use. There are four freedoms that every user
should have:
 the freedom to use the software for any purpose,
 the freedom to change the software to suit your needs,
 the freedom to share the software with your friends and neighbors, and
 the freedom to share the changes you make.
 When a program offers users all of these freedoms, we call it free software.
1 www.gnu.org
Linux Overview
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Linux Distributions
 Red Hat (Enterprise) Linux is probably the largest commercial Linux vendor.
Focus on stability and long term support. Red Hat sponsors a community
version (Fedora) which undergoes a more rapid development cycle.
 KNOPPIX – The first Live CD version. The OS can be booted from, and run
completely off the CD. KNOPPIX is based on Debian Linux. Many vendors
now offer Live versions. No installation necessary.
 Ubuntu based on Debian Linux. Ubuntu claims to be most popular desktop
version. Many applications and excellent “update mechanism” contribute to
its sucess. Revenue is created by selling technical support.
 Puppy – This distribution is small enough to be loaded entirely in RAM. This
frees up the CD/DVD drive for other uses. Configuration can be saved to a
file between reboots.
 Recovery Is Possible (RIP) good for data recovery of corrupted media or
backup. Tools such as ddrescue allows copying media sector by sector. Can
repair NTFS or FAT partitions.
Linux Overview
10
Applications
 Samba is a free implementation of the Server Message Block (SMB)
protocol used by Microsoft Windows network file system. Allows
sharing files, print services, and can even act as a domain controller.
 Apache is the most popular HTTP server software on the internet.
 Rsync allows synchronizing directories/files locally or across a
network. Suited for low bandwidth as only changes get propagated
across network.
Linux Overview
11
Other Open Source Software
 The GIMP - Adobe Photoshop clone
 Open Office - Office suite
 Mozilla Firefox - Web browser
 Mozilla - Thunderbird E-mail Client
 VLC - Media player
 Audacity - Digital audio editor
 MySQL – Database
 Ghostscript - Postscript interpreter
Linux Overview
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Possible Uses
 Various tools permit user to recover data, repair/modify partitions,
backup and clone various types of media. “DD type” tools allow
copying a storage device by blocks/sectors. This allows duplicating a
device without “knowing the filesystem”.
 Linux can natively communicate with DECNET protocol. This allows
a Linux PC to act as an End Node in a VMS cluster. Other DECNET
tools allow additional inter-connectivity between the two OSs.
 With Samba and Ghostscript a Linux PC can be a Windows PDF
print server. Giving individuals the ability to create PDF files without
buying Adobe Acrobat or installing additional applications on each
computer.
Linux Overview
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Who uses it
 NSA created Security Enhanced Linux (SELinux) to develop better
allow the control of dynamic security policies. The architecture they
created has been mainstreamed into Linux and ported to other
operating systems including Solaris, and Free BSD.
 IBM, HP, and Sun contribute heavily to Linux and OSS
 Even Microsoft’s position on OSS has softened and they are now
contributing code to various projects.
Linux Overview
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Misc Information
 The Linux Documentation Project provide HOWTOs and Guides to
accomplish many Linux specific tasks.
 Linux runs on a wide range of processors from embedded devices
such as cell phones to supercomputers employing Linux clusters.
One estimate from Forbes.com estimates that 60% of the worlds top
500 computers runs Linux.
 The availability of the OS source code allows it to be customized and
tailored to users needs.
Linux Overview
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Web sites for more info and software
 Sourceforge.net
 Freshmeat.net
 Distrowatch.com
 Kambing.ui.ac.id
 www.linux.org
 Tldp.org The Linux Documentation Project
Linux Overview
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What are the benefits of Linux?
Linux can give you:
A modern, very stable, multi-user, multitasking environment.

Advanced graphical user interface. Linux uses a standard, network
transparent X-windowing system with a "window manager" (typically
KDE or GNOME but several are available).

The graphical desktop under Linux can be made to look like MS
Windows (or probably ANY other graphical user interface of your
choice).

Dozens of excellent, free, general-interest desktop applications.
These include a range of web browsers, email programs, word
processors, spreadsheets, bitmap and vector graphics editing
programs, file managers, audio players, CD writers, some good
games, typing tutor, etc.
Freedom from viruses. Linux has no viruses because it is too
secure an operating system for the viruses to spread with any
degree of efficiency.
Linux is quite positively here-to-stay because of its open-source
nature (Linux cannot possibly be put out-of-business). It is a
standard selected for countless projects that are not going to go
away, and some of them are quite "mission-critical." Try the
International Space Station, for which Linux is the operating syste
(http://www2.linuxjournal.com/lj-issues/issue59/3024.html).
In a nutshell, the GNU General Public Licence (GPL) allows
anybody to:
use the software at no charge, without any limitations,

copy, and distribute or sell unmodified copies of the software
in the source or binary form,

use the software with propriatory (e.g., your own)
modifications, free of charge, as long as you do not distribute
or sell the modified version,

modify, and distribute or sell a modified version of the
software as long as the source code is included and licenced
on the same terms as the original you received (the GPL),

sell support for the software, without any limitations.

What the GPL license *does not* allow code recipients to do is to
take somebody elses software licenced under GPL, modify the
software, and then distrubute a this modified version of the softwar
under a propriatory licence. Speaking plainly, the GPL licence just
forbids stealing existing (somebody else's) software for incorporatio
into a closed, commercial-only product.
I need warranty and security. With
commercial software, I can sue if
things go wrong.
Things go wrong on many MS Windows NT machines every day,
and there are no damages awarded by courts. Read your MS
Windows license agreement to find out that there is no guarantee
whatsoever that ANYTHING will work. Trying to sue would be a
waste of your money.
Linux Distros
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A Linux distribution, often simply distribution
or distro, is a member of the Linux family of
Unix-like computer operating systems.
Distros mainly based on ‘Look and Feel’ and
Applications
Distros:
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Red Hat Fedora, Debain, SuSe,Ubuntu,
Gentoo,……..
File System
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Windows uses letters of the alphabet to
represent different devices and different hard
disk partitions. Under Windows, you need to
know what volume (C:, D:,...) a file resides on
to select it, the file's physical location is part
of it's name.
In Linux all directories are attached to the root
directory, which is identified by a forwardslash, "/". - root.
For example, below are some second-level
directories:
•
/bin System binaries, including the command shell
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/boot Boot-up routines
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/dev Device files for all your peripherals
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/etc System configuration files
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/home User directories
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/lib Shared libraries and modules
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/lost+found Lost-cluster files, recovered from a disk-check
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/mnt Mounted file-systems
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/opt Optional software
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/proc Kernel-processes pseudo file-system
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/root Administrator’s home directory
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/sbin System administration binaries
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/usr User-oriented software
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/var Various other files: mail, spooling and logging
Linux Help
man
 info
 command –help
 Forums.
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man command
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The “-k” option
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Manual pages are divided in 8 sections:

User commands
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System calls
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Libc calls
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Devices
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man –k print
File formats and protocols
Games
Conventions, macro packages and so
forth
System administation
To select correct section, add section number:

man 1 passwd, man 5 passwd
info command
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A program for reading documentation,
sometimes a replacement for manual pages
Example : info ls
Links :
http://en.wikipedia.org/wiki/Unix
http://en.wikipedia.org/wiki/Linux
Download Source Code from:
http://www.kernel.org
Books:
Unix User Guide – Rebecca Thomas
Your UNIX: The Ultimate Guide-Sumitabha
Das
Thank you