Linux Basics

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LinuxBasics
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What is an Operating System (OS)?

• An Operating System (OS) is an interface between
  hardware and user which is responsible for the
  management and coordination of activities and the
  sharing of the resources of the computer that
  acts as a host for computing applications run on
  the machine.

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What is an Operating System (OS)?

• An Operating System is a computer program that
  manages the resources of a computer. It accepts
  keyboard or mouse inputs from users and displays
  the results of the actions and allows the user to
  run applications, or communicate with other
  computers via networked connections.

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Functions Of Operating System

• Today most operating systems perform the
  following important functions
• 1. Processor management, that is, assignment of
  processor to different tasks being performed by
  the computer system.
• 2. Memory management, that is, allocation of main
  memory and other storage areas to the system
  programs as well as user programs and data.
• 3. Input/output management, that is,
  co-ordination and assignment of the different
  output and input device while one or more
  programs are being executed.
• 4. File management, that is, the storage of file
  of various storage devices to another. It also
  allows all files to be easily changed and
  modified through the use of text editors or some
  other files manipulation routines.

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Common Operating Systems

• The primary operating systems in use are Windows
  (Windows 98, XP, Vista, 7, 8), Macintosh OS X,
  the many versions of Linux and Unix. DOS is still
  used for some applications, and there are many
  other special-purpose operating systems (Embedded
  Linux).
• Android is a mobile operating system (OS) based
  on the Linux kernel and currently developed by
  Google.

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What is Linux?

• The GNU operating system is a complete free
  software system, upward-compatible with Unix. GNU
  stands for GNU's Not Unix. Richard Stallman
  made the Initial Announcement of the GNU Project
  in September 1983. A longer version called the
  GNU Manifesto was published in September 1985. It
  has been translated into several other languages.
• Linux is an operating system that was initially
  created as a hobby by a young student, Linus
  Torvalds, at the University of Helsinki in
  Finland. Linus had an interest in Minix, a small
  UNIX system, and decided to develop a system that
  exceeded the Minix standards. He began his work
  in 1991 when he released version 0.02 and worked
  steadily until 1994 when version 1.0 of the Linux
  Kernel was released. The kernel, at the heart of
  all Linux systems, is developed and released
  under the GNU General Public License and its
  source code is freely available to everyone. It
  is this kernel that forms the base around which a
  Linux operating system is developed. There are
  now literally hundreds of companies and
  organizations and an equal number of individuals
  that have released their own versions of
  operating systems based on the Linux kernel.

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Richard Stallman, father of the GNU Project
Linus displays Linux running on a notebook pc
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Linux Kernel

• The Kernel is the heart of the Linux operating
  system, responsible for controlling the
  computers resource and scheduling user jobs so
  that each one gets its fair share of the
  resources. Programs interact with the kernel
  through special functions with well-known names,
  called system calls.

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Different Distributions of Linux

• Red Hat http//fedoraproject.org
• CentOS http//www.centos.org/
• Ubuntu http//www.ubuntu.com
• Mandrake http//www.linux-mandrake.org
• Debian http//www.debian.org
• Knoppix http//www.knoppix.net/

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CentOS(http//www.centos.org)Cent OSs main
advantage over RedHat enterprise is the fact that
it is free.
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Download ISO image file from http//mirror.centos
.org/centos/5/isos/ orhttp//mirror.centos.org/ce
ntos/6/isos/Burn CDBurnerXP orNero Burning ROM
How to Get CentOS
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See Installation Guide (http//www.centos.org/doc
s/5/html/5.2/Installation_Guide/)CentOS 5
Installation Process(http//www.ee.cuhk.edu.hk/h
tlau/CentOS5InstallationProcess.ppt)
Installation
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After installation, remember to start the
services (SSH, FTP, Web, etc.) you want to run by
using System Administration Server Settings
ServicesSSH and FTP already started Web
httpd
Start Services
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Environment

• Menu
• Software Collection (Firefox, OpenOffice,
  multimedia software, etc.)
• Similar to Windows and quite easy to use
• But Linux is mainly used to act as free (SSH,
  Web, FTP, Email, etc.) server

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SSH Server

• Up already after installation
• Use terminal to try. Other computers can use SSH
  client or PuTTY to connect to SSH server
• PuTTY can be downloaded from http//winscp.net/dow
  nload/putty.exe
• SSH client can be downloaded from
  https//www.cuhk.edu.hk/itsc/ssh/index2.html

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FTP Server

• Up already after installation
• Other computers can use Secure File Transfer
  Client or WinSCP to connect and then upload or
  download files
• WinSCP can be downloaded from http//winscp.net/do
  wnload/winscp556.zip

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Apache Web Server

• You may use other computers (Frontpage,
  Dreamweaver, etc.) to create homepage and then
  use FTP or USB drive to copy the homepage files
  to /var/www/html/
• Other computers use browsers to connect to
  http//hostname or http//IPAddress, e.g.,
  http//137.189.35.222

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Linux Documentation

• The Linux Home Page at Linux Online
  (http//www.linux.org/)
• ??? Linux ??? (http//linux.vbird.org/)
• Google (use it to search useful information)
• Basic UNIX commands (http//mally.stanford.edu/sr
  /computing/basic-unix.html)

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CentOS Documentation

• The most useful documentation (http//www.centos.o
  rg/docs/5/html/5.2/Deployment_Guide/)