CMPF 124:Basic Skills for Knowledge Workers

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CMPF 124Basic Skills for Knowledge Workers

• INTRODUCTION TO LINUX OPERATING SYSTEMS

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Chapter Overview
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Introduction and History of Linux
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What is Linux?

• An operating system
• Linux has a reputation as a very efficient and
  fast-performing system.
• Free, open source, software
• A community

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Introduction

• Unix was developed in the mid-1970s when
  minicomputers and mainframe were popular
• The problem with Unix is its inaccessibility by
  programmers and developers
• The earlier commercial versions of Unix were
  costly, sometimes costing more than a pc hardware
• Linux began by Linus Torvalds at the University
  of Helsinki, Finland
• Linux today was developed with assistance of
  programmers worldwide

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History

• Developed as project of Linus Torvalds, student
  at University of Helsinki
• Based on Minix, small Unix OS
• First release in 1991 with version 0.02
• Version 1.0 was released in 1994
• Current stable version is 2.6.24

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Linux Systems and Distributions
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Linux OS Distributions

• Many different distributions
• Private
• Usually specialized
• Firewall
• Minimal install
• Floppy disk Linux
• Language specific

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Linux OS Distributions (cont.)

• Linus Torvalds created Linux and distributed
  early versions across the Internet for the
  enjoyment of many hardcore hackers
• Today, Linux is distributed in many ways,
  including CD-ROMs, tapes, Internet and even
  inside diskettes
• A Linux distribution has the utilities and other
  programs in Unix

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Linux OS Distributions (cont.)

• Linux is constantly evolving and hardware support
  is frequently updated
• Not many hardware are compatible with Linux
• But the compatibility of hardware has improved
  since Linux gain more popularity nowadays
• To date, Linux has proven more popular in the
  server market, primarily for Web and database
  servers than in the desktop market.

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Linux OS Distributions (cont.)

• Corporate
• Continually improving installs
• Larger device and standard support
• Large amount of packages (programs) usually 3-4
  CDs worth
• Big names Red Hat, Mandrake, SuSE

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List of Linux Distributions

• There are a number of Linux distributions across
  the world
• A few most popular distributions
• Debian - The Debian distribution and Debian
  Project are governed by a social contract that
  requires that OSes produced by Debian will be
  100 "free," as determined by the Debian Free
  Software Guidelines (DFSG)
• Fedora - Formerly known as Fedora Core, is a
  Linux distribution sponsored primarily by Red
  Hat, with significant community participation.
  The Fedora Linux produced by the Fedora Project
  was based on the original Red Hat Linux
  distribution and is made up entirely of free and
  open source software
• Knoppix - One of the most popular live CD Linux

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List of Linux Distributions (cont.)

• openSUSE - The openSUSE project is sponsored by
  Novell to create a base for the SUSE Linux
  distribution it sells and supports. The openSUSE
  distribution is worked on by Novell employees and
  community members, and is suitable for desktop
  and server use
• Slackware - Slackware Linux is the world's oldest
  surviving Linux distribution
• Ubuntu - A popular community-developed Linux
  distribution for laptops and desktop machines,
  and is also gaining popularity on servers. Ubuntu
  is based on Debian GNU/Linux, and also serves as
  the foundation for several other Linux
  distributions in its own right

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The OS

• Linux refers to the kernel, the core of the OS
• The kernel is what actually makes the computer
  run
• Developed under the GNU General Public License

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GNU General Public License

• Sponsored by the Free Software Foundation
• A method for a program author to provide the code
  yet protect it from becoming proprietary
• Any program developed under this license can be
  changed at will
• However, no money can be charged for the code
  itself, it must be freely available
• Can charge for support, development and
  distribution costs

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GNU Linux Tools

• GNU stands for GNUs Not Unix
• Richard Stallman created the foundation to help
  write free versions of the Unix software tools
• Linux benefits from most of these tools, which is
  why often youll see GNU/Linux

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Manipulating Linux GUI
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Linux OS Details

• Multitasking OS
• Every application has their own memory space
• The kernel keeps track of everything
• Multiuser
• One computer can serve the needs of many users at
  once
• Each user can have different settings for the
  same application
• Standard Unix/Linux concept

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Networking

• Unix built the Internet
• All networking protocols are supported (IPv4,
  IPv6, Wireless, NFS, SMB)
• Web servers, file servers, firewalls, NAT
  machines to name a few

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Some Added Features

• Programmable shells
• Linux is the most flexible OS available where
  programmers can write their own programs inside
  Linux shells
• Device independence under Linux
• Linux is device independence as well as Unix
• Programmers all around the world developed
  drivers of many hardware for Linux

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Windows Interface

• Since no one company controls everything, there
  are numerous desktop environments
• Each is just as interface to the X window system
  tools
• The two most popular are KDE and GNOME
• Most window managers have features like multiple
  desktops per user

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Windows Interface (cont.)
KDE
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Windows Interface (cont.)
GNOME in Red Hat 9
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Linux Command-line Interface
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Linux Command Lines

• ls
• The ls command is used to list the contents of a
  directory. It is probably the most commonly used
  Linux command. It can be used in a number of
  different ways. Here are some examples
• ls list the files in the working directory
• ls /bin list the files in the /bin directory
  (or any other directory you want to specify)
• ls l list the files in the working directory
  in long format
• ls l /etc /bin list the files in the /bin
  directory and the /etc directory in long format
• ls la list all files (even ones with names
  beginning with a period character, which are
  normally hidden) in the parent of the working
  directory in long format

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Linux Command Lines (cont.)

• cp
• The cp program copies files and directories.
  Examples
• cp file1 file2 copy a single file
• cp file1 file2 file3 directory copy multiple
  files to a different directory

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Linux Command Lines (cont.)

• mv
• The mv command performs two different functions
  depending on how it is used. It will either move
  one or more files to a different directory, or it
  will rename a file or directory. Examples
• mv file1 file2 rename a file
• mv file1 file2 file3 directory move files to a
  different directory

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Linux Command Lines (cont.)

• rm
• The rm command deletes (removes) files. Example
• rm file
• rmdir
• The rmdir command deletes directories. Example
• rmdir directory
• mkdir
• The mkdir command is used to create directories.
  Example
• mkdir directory

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Linux Command Lines (cont.)

• man
• Online help for each of the various Linux
  commands
• Linux will display any information you type
• Example
• man ls it will show description of ls command
• more
• Display a screenful of a text file
• You can look through a text file without invoking
  an editor, printing the file, or trying to pause
  the terminal as it displays the file

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Linux System Administrator

• Every aspect of the system can fall within the
  realm of a system administrator
• Entire books have been written about just the
  software side, and for most system
  administrators, hardware, networks, and even
  programming fall into their laps
• Almost every user, and many administrators, never
  see what is happening as the system is booting

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Linux System Administrator (cont.)

• Those who do often are not sure what is
  happening. From the time you flip the power
  switch to the time you get that first login
  prompt, dozens of things must happen, many of
  which happen long before the system knows that
  its running Linux
• Knowing what is happening as the system boots and
  in what order it is happening is very useful when
  your system does not start the way it should

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Overview of Linux Software and Tools
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The Boot Process

• The process of turning on your computer and
  having it jump through hoops to bring up the OS
  is called booting, which derives from the term
  bootstrapping
• The process a computer goes through is similar
  among different computer types, whether it is a
  PC, Mac, or SPARC Workstation

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LILO The Linux Loader

• This is basically a set of instructions to tell
  the OS how to boot
• That includes what OS to boot and from what
  partition, as well as a number of different
  options
• If LILO is installed in your master boot record,
  it can be used to boot basically any OS that you
  can install on that hardware
• Actually, most of the work was done by the boot
  loaders of the respective OS, but LILO was used
  to load start the boot process

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User Accounts

• Users gain access to the system only after the
  system administrator has created user accounts
  for them
• These accounts are more than just a user name and
  password they also define the environment the
  user works under, including the level of access
  he/she has

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User Accounts (cont.)

• Users are added to Linux systems in one or two
  ways.
• You could create the necessary entries in the
  appropriate file, create the directories, and
  copy the start-up files manually
• Or, you could use the adduser command, which does
  that for you

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Linux Community

• Linux is by its nature a community
• The OS and applications only move forward by the
  help of many
• Help is a HOW-TO or a mailing list away
• Google.groups are an excellent source of
  information
• Linux Documentation Project is a huge resource of
  HOW-TO documents written by the community

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Linux Software

• Thousands of programs already run on Linux
• Office suites, games, web development tools are
  probably the most lacking, although more are
  always developed
• OpenOffice is now available and very versatile

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Basic Linux Administration
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Linux Users

• Root
• Controls all system files
• Only user that can do anything, even look
  at/delete another users files
• Usually the only user that can install most
  programs
• Normal users
• Each has a home directory
• Files are separated from other users
• Cannot edit system data/configuration
• Often cant even see system data

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Basic File Structure

• Hard disk is divided into partitions
• Usually a minimum of 2 / (root) and /home
• Idea is to keep user data and system data
  separated to prevent problems
• Users 2 minimum
• Super user (root)
• At least one regular user

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File Permissions

• Every file and directory has three sets of
  permissions
• Read (r) can read the file
• Write (w) can write, change and delete the file
• Execute (x) an executable script/file
• Permissions can then be set for three different
  groups
• User the person that owns (created) the file
• Group the group the user belongs to
• Others everyone else

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Useful Programs

• OpenOffice Sun Microsystems office suite
• http//www.openoffice.org
• Samba Windows connectivity client and server
• http//www.samba.org
• Apache Web Server the standard on the Internet
• http//www.apache.org

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Useful Programs (cont.)

• PHP scripting language create dynamic web pages
• http//www.php.net
• GIMP powerful image program comparable to
  Photoshop
• http//www.gimp.org
• MySQL Database free, powerful, easy to use
• http//www.mysql.com

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The End

• CMPF 124
• Basic Skills for Knowledge Workers