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Introduction to Linux
Contents
Introduction
History of Linux
Concepts to be known
Ubuntu 14.04 LTS setup
A free Unix-type operating system developed under the GNU General Public License.
Open source
Popular
Support most of the platforms available
Linux
History of Unix OSThe Unix OS was developed (based on Multics & CTSS
operating systems) by Ken Thompson at the AT&T Bell
Laboratories in 1969. He wanted to create an multi-user
operating system to run “space wars” game.
Ken’s philosophy was to create an operating system
with commands or “utilities” that would do one thing
well (i.e. UNIX). Pipes could be used combine
commands...
History of Unix OSThe first versions of UNIX were written in
“machine-dependent” program (such as PDP-7).
Ken Thompson approached Dennis Ritchie,
developer of C language, and in 1973 they
compiled UNIX in C to make operating system
“portable” to other computers systems.
UNIX Features
The Unix OS is a multi-user OS allowing more
that more person to directly communicate with the
computer.
Although the OS can only work on one task at a
time, a small piece of time (time slice) is dedicated
to each task/user –this referred to as “time-sharing”
Illustration of
Time-Sharing
TIME
User 1
User 2
User 3
User 4User 5
User 6
User 7
User 8
Development of Unix OS
Unix became a popular OS among institutions such as
colleges & universities through a 4-year “try before you
buy” deal.
− Efficient and inexpensive way of networking
− promotes Internet use and file-sharing
− Open system allows for source code to be shared among many
programmers - allows for better coordination among
programmers
Development of Unix OS
Students at University of California (in Berkley)
further developed the UNIX operating system
and introduced the BSD version of UnixUnix
Bell Labs
UNIX System V (5)
Proprietary
Berkley Software Distribution (BSD)
Free
Development of Unix OS
There were versions of UNIX for the Personal
Computer (PC), such as XENIX, etc., but they
didn’t catch on in popularity until Linux was
developed in the early 90’s.
History of Linux
Linux operating system
developed by
programming student
Linus TorvaldsLinus wanted to develop
Unix-like OS just to experiment with new 386 computer at the time...
Why Linux became so popular?
Linus decided to make Linux OSsource-code for Linux Kernel open to all:
− Unlike traditional Operating Systems, anyone can modify and distribute Linux OS (as long as they distribute source code of Linux Kernel)
− “Competition among Hackers” allow code to be improved and distributed often
− Many users can spot bugs in the operating system or application if source code is “open”
Other Factors:
− PC’s have increased processing power and there has been
a noted shift from mainframes and minicomputers to PCs.
− Since Linux is a “Unix Work-alike”, this OS has a
reputation to be a very stable platform for networking
(creating at-home servers) and running / maintaining
applications.
− Agencies such as Free Software Foundation created GNU
project to provide free software.
Why Linux became so popular?
ConcernsSome people claim that “there are as many version of
Linux as there are users…”
POSIX (Portable Operating System Interface for
Computer Environments) is a government standard to
ensure consistency among different UNIX and Linux
versions.
Many versions of Linux are approaching POSIX
standard.
− Multics, AT&T Bell Lab, GE, MIT
− 1969, UNIX, Ken Thompson, Dennis Ritchie
− 1973, Rewrite UNIX with C
− Berkeley UNIX(BSD UNIX)
− Commercial productsSunOS, Solaris, HP-UX, AIX, SCO UNIX
A Short History of UNIX
A Short History of Linux
A Short History of Linux(2)
Is Linux difficult ?
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 system (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 software under a propriatory licence. Speaking plainly, the GPL licence just forbids stealing existing (somebody else's) software for incorporation into a closed, commercial-only product.
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
Linux Distros
: Distros:
Red Hat Fedora, Debain, SuSe,Ubuntu,
Gentoo
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 forward-slash, "/". - root.
For example, below are some second-level directories:
File System
• /bin System binaries, including the command shell
• /boot Boot-up routines
• /dev Device files for all your peripherals
• /etc System configuration files
• /home User directories
• /lib Shared libraries and modules
• /lost+found Lost-cluster files, recovered from a disk-check
• /mnt Mounted file-systems
• /opt Optional software
•/proc Kernel-processes pseudo file-system
• /root Administrator’s home directory
• /sbin System administration binaries
•/usr User-oriented software
• /var Various other files: mail, spooling and logging
man info command –helpForums.
Linux Help
− The “-k” option
man –k print
− Manual pages are divided in 8 sections:
User commands
System calls
Libc calls
Devices
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
man command
info command
A program for reading documentation, sometimes a replacement for manual pages
Example : info ls
Ubuntu
What is it?
Ubuntu is a Linux-based Operating System that is
open sourced (free)
Pronounced (oo-BOON-too)
Strong focus on usability and ease of installation
Why that name?
Ubuntu is an African concept meaning “humanity
toward others”
Sponsored by Canonical Ltd. Owned by South African
billionaire Mark Shuttleworth
Why use it?
Huge group of “free software proponents” (open
source)
Ubuntu is free
Alternate to Windows and MAC OS’s
Ubuntu is most popular Linux-based OS in the
world (8 million now)
Dell now offers desktops with Ubuntu
Last version – Feisty Fawn 7.04
Latest version – Gusty Gibbon 7.10
Next version – Hardy Heron 8.04 in 2011
256 KB RAM
4 GB hard drive space
Can be dual booted with current OS or used from a
live CD
Gutsy Gibbon Software Includes:
Firefox browser
Thunderbird and Evolution e-mail
Open Office suite
GIMP (Photoshop-like)
Music and Video players
Games
Summary
Pro –
Open source (free too)
Upgrade available about every 6 mo.
Compatible with MS programs
Many add-ons available
No key codes, activation, registration
Summary
Con’s
No tech support (Internet groups only)
Not all programs compatible
Drivers for peripherals not always available
How to get Ubuntu
Three ways to acquire:
1. Download from the Internet
www. Ubuntu. Com
Warning: about 600 MB download
2. Send for a free CD
Links :http://en.wikipedia.org/wiki/Unixhttp://en.wikipedia.org/wiki/LinuxDownload Source Code from:http://www.kernel.orgBooks:Unix User Guide – Rebecca ThomasYour UNIX: The Ultimate Guide-Sumitabha Das
Thank you