Introduction to Linux

LINUX PROGRAMMING AND ADMINISTRATION

PRESENTED BY

HARISH.R

OVERVIEW OF PRESENTATION

INTRODUCTION TO UNIX AND LINUX

FILES AND DIRECTORIES IN LINUX

INSTALLATION IN LINUX

BASIC COMMANDS

USER AND GROUP ADMINISTRATION

LILO

UNIX

HISTORY OF UNIX

MULTICS

UNICS

UNIX

Started in 1965 by AT & T, GE MIT

Created by Ken Thompson in 1969

Written in 100% C Language and released in 1973

UNIX

Commercial products

1. SunOS, Solaris

2. HP-UX

3. AIX

4. SCO UNIX

What is GNU / UNIX

A free Unix-type operating system developed under the

GNU General Public License.

Open source

Popular

Support most of the platforms available

General Characteristics of UNIX

Multi-user & Multi-tasking

Over 30 Years Old.

Large Number of Applications

FLAVOURS OF UNIX

These can be grouped into two categories: Open Source and Proprietary

Proprietary: (redistribution and modification prohibited or restricted; not free)

Solaris

IRIX

Mac OS X

Open Source: (source code is readily available and free to modify)

RedHat

Debian

SuSE

Slackware

History of LINUX

In Sept 1991, Linus Torvalds, a second year student of

Computer Science at the University of Helsinki, developed the

preliminary kernel of Linux, known as Linux version 0.0.1

CHARACTERISTICS OF LINUX

is a Unix-like computer operating system

Predominantly known for its use in servers.

supported by corporations such as Dell, Hewlett-Packard, IBM, Novell, Oracle

Corporation, Red Hat, and Sun Microsystems

USED AS AN OPERATING SYSTEM

Computer hardware

desktop computers

supercomputers

Video game players

PlayStation 2

PlayStation 3

Several Arcade Games

Embedded devices

Mobile Phones

Routers

Wristwatches

Stage lighting systems

Where might you find Linux?

LINUX DISTRIBUTION

Red Hat Linux

Open Linux

Debian GNU/Linux

SuSE Linux

Mandrake Linux

Slackware

LINUX DISTRIBUTION

Features of Linux

OPEN SOURCE: Free Software along with source code and Documentation.

MULTITASKING: Capable of running multiple application and process at the same time.

MULTIPLE-USER: Allow Multiple user to login and use the resources at same time.

PORTABILITY : Can be installed on all hardware architecture.

Features of Linux

SCALABILITY : Same Operating Systems can be used on a desktop to a Super Computer.

RELIABILITY : Large Server have been successfully being running without a single second of down time.

USER INTERFACE

Linux can be controlled by

text-based command line interface (CLI)

graphical user interface (GUI) (usually the default for desktop)

through controls on the device itself (common on embedded machines)

On desktop machines, KDE, GNOME and Xfce are the most popular user interfaces

File system hierarchy standard (fhs)

/

bootroot bin

optdevusrsbinhom

e

mediaetcvar

LINUX INSTALLATION

WHAT IS A PARTITION

A partition is a means of dividing your hard disk into multiple sections,

each of which is treated as a separate disk by your operating system.

This allows you to be able to boot different operating systems from the

same disk, for example, Linux and Windows.

Partitions cannot be moved or resized without destroying the data on

them.

WHAT IS A FILE SYSTEM

File systems can be considered as being the directory

structures on a disk partition that contains all the files.

Most Windows users would be familiar with the analogous

terms "folders" and "subfolders", whereas Linux users would be

familiar with the terms "directories" and "sub-directories".

/boot partition

The /boot partition contains the Linux kernel which is the "master

control program", not only for controlling the boot process, but also

the normal functioning of Linux.

Redhat Linux creates this partition automatically. This reduces the

need to reformat the "root" partition if it becomes corrupted.

SWAP PARTITION

Used as a location to place data temporarily if RAM memory becomes full.

Red Hat automatically creates this partition and usually makes it about

twice the amount of system RAM.

To create swap partition

]#fdisk /dev/partition name

N=new

L=logical

SWAP PARTITION

Format swap

]#mkswap /dev/partition name and ID

To on the swap

]#swapon /dev/partition name and ID

HARDWARE REQUIREMENTS

PROCESSOR MINIMUM RECOMMENDED

RAMTEXT 96 MB 256 MB

GUI 128 MB 512 MB

HARD DISK

TEXT 1 GB As per requirement

GUI 3 GB As per requirement

RECOMMENDED PARTITIONS

Partitions Size

/boot 100 MB

/ 3000 MB

/usr 6000 MB

/var 2000 MB

/home 2000 MB

swap Twice the RAM ( Minimum 4 GB )

Red hat installation

DUAL BOOT UBUNTU INSTALLATION

BASIC COMMANDS IN LINUX

Print working directory

Print the name of the current working directory

[root@comp~]# pwd

List of files and directories

Options:

-l Long list including attributes

-a All files and directories including hidden.

-d For a particular file or directory.

-R Recursive to see the tree.

To see the list of files and folders

[root@comp~]# ls <options> <arguments>

Creation of files

Files can be created by using any of the three methods given below:

Cat command

Touch command

Vi editor

Cat (concatenation command)

To create a file

[root@comp~]# cat > <filename>

To view the contents of the file

[root@comp~]# cat <filename>

Touch command

To create a zero byte file

[root@comp~]# touch <filename>

To create a multiple zero byte file

[root@comp~]# touch <first file> <second file> <third file>

Vi editor

To create a file

[root@comp~]# vi <filename>

Creating a directories

To create multiple directories

[root@comp~]# mkdir <first dir> <second dir> <third dir>

To create a directory

[root@comp~]# mkdir <file name>

Copying

Options:

-r Recursive

-v Verbose

-p Copy with permissions

To copying a file or directory

[root@comp~]# cp <options> <source file> <destination file>

Moving and renaming

To move a file or directory to a different locations

[root@comp~]# mkdir <source file or directory> <destination>

Rename a file or directory

[root@comp~]# mv <old name> <new name>

Deleting

Options

-r Recursive

-f forcefully

To remove or delete an empty directory

[root@comp~]# rmdir <dir name>

To remove or delete a file or directory

[root@comp~]# rm <options> <file or dir name>

Other commands

To see the date

[root@comp~]# date

To see the calender

[root@comp~]# cal

Vi EDITORS

Editors

Editors are used for adding, modifying and / or deleting text.

The different editors used

• Windows :notepad

• LINUX / UNIX zx

1.CLI Based : EX, ED, VI

2.GUI based : Emacs, Gedit, nedit, nano, pico

Vi Editors

Vi editors is a screen oriented text editors written by Bill joy in 1976.

This is the most commonly used editor for editing files in Linux.

Vi editor modes

Vi editors has three modes of operations

Command modeInsert modeEx mode

Insert mode

i - Inserts the text at the current cursor position.

I - Inserts the text in beginning of line.

a - Adds the text after the current cursor position.

A - Adds the text at the end of the line.

o - Insert the text one line below current cursor point.

O - Insert the text one line above current cursor point.

Command mode

dd - Deletes a line. ndd - Deletes ‘n’ lines. yy - Copies a lines. nyy - Copies ‘n’ lines. p - Put (Paste the deleted or

copied text). u - Undo (you can undo 1000 times)

Ex mode

:q - Quit without saving. :w - Write(save). :wq - Save and quit. :se nu - Set line numbers. :se nonu - Remove line numbers. :88 - This cursor goes to line

84.

USER ADMINISTRATION

Users

In computing, a user is a person who uses a computer or internet service.

A user will have a user account that identifies the user by a user name.

To logon a system, a user is required to authenticate himself with a password for the purposes of accounting, security, logging.

Users

Red hat Linux uses a User private group scheme

When a user is created a group with the same as the user name is also created.

This becomes the primary group.

A user can have only primary group.

Users

When a user is created in UNIX and LINUX, the following are also created by default.

Home directory /home/[username]

Mail account /var/spool/mail/[username]

Unique user identifier (UID) and the Group Identifier (GID).

Creating a user

Adding a user

[root@comp~]# useradd <username>

Or

[root@comp~]# useradd <options> <arguments> <username>

Options for creating user

Options:

-u UID

-c Comment

-g Primary group name

-G Secondary group name

-d Home directory

User password

Creating or changing a user password

[root@comp~]# passwd <username>

Modifying a user

Options:

-l Change the login name.

-L Lock the account.

-U Unlock the account.

Modifying user properties

[root@comp~]# usermod <options> <arguments> <username>

Deleting a user

Options:

-r Recursively

Deleting a user

[root@comp~]# userdel <options> <arguments> <username>

GROUP ADMINISTRATION

Group

Group is a collection of user to whom the same permission are to be applied.

There are two types of groups

1. Primary

2. Secondary

Creating a group

Options:

1. -g GID

Creating a group

[root@comp~]# groupadd <group name>

Or

[root@comp~]# groupadd <options> <arguments> <group name>

Modifying a group

Options:

-g GID

-n Group Name

Modifying a group

[root@comp~]# groupmod <options> <arguments> <group name>

Deleting a group

Deleting a group

[root@comp~]# groupdel <options> <arguments> <username>

ACCESS PERMISSIONS

Access Permissions

There are three defined categories of users.

The categories are:

owner — The owner of the file or application.

others — All users with access to the system.

group — The group that owns the file or application.

Access permissions

There are three permissions for any file, directory or application program.

The following lists the symbols used to denote each, along with a brief description:

r — Indicates that a given category of user can read a file.

w — Indicates that a given category of user can write to a file.

x — Indicates that a given category of user can execute the file.

LILO

Introduction to LILO

LILO or Linux Loader is a boot loader for Linux.

A boot loader is a small program that exists in the system and loads the operating

system into the system’s memory when the system boots.

Boot loader also starts the operating system.

LILO

LILO is a flexible boot loader for Linux, which is independent of a file system.

LILO loads itself into the computer’s memory in two stages

Stage1 – This stage, also known as primary boot loader is read into

memory by the BIOS from the master boot record

Stage 2 - This stage, also known as secondary boot loader is read into memory and it displays the Red Hat Linux initial screen

Configuring LILO

To install LILO, it is necessary to know the location of /boot partition.

It is also necessary to know the location of other installed operating systems

LILO can be installed for the first time using a shell script named QuickInst

LILO can be uninstalled using the lilo –u command

NETWORK FILE SYSTEM (NFS)

A network file system is any computer file system that support sharing of files over a computer network..

It is a centralized file storage system.

The client cannot differentiate whether the file is stored locally or remotely.

NETWORK FILE SYSTEM (NFS)

The Nfs Environment Contains The Following Components:

Nfs Server

- A System That Contains The File Resources To Be Shared With Other System Over The Network.

Nfs Cilent

- A System That Mounts The File Resources Shared Over The Network And Presents The File Resources As If They Were Local

DISK QUOTAS

Quotas are used to restrict the amount of hard disk spaces occupied by a user.

BACKUP

Backup is copy of data on a computer system.

,

Backup Levels

1. Level 0

2. Level 1

3. Level 2

BACKUP UTILITIES

tarCpio

Software tools in LINUX

Office Productivity suites

1. Applix ware

2. Star office

3. Corel office

Graphical tools

GIMP

File Transfer Protocol

File transfer protocol (FTP) is one of the oldest member of the TCP/IP protocol stack and is still in common use.

As the name suggests, it is optimized for transferring files.

FTP Server for LINUX

vsFTP Very Secure FTP Daemon

WU-FTP Washington University’s (St. Louis)

Proftpd Professional FTP Daemon

FTP Commands

ls

cd

put

mput

get

mget

bye

DIFFERENCE BETWEEN LINUX AND MICROSOFT

LINUX

Cost: Open Source, freely downloaded from Internet.

Usage: installed on a wide variety of computer hardware, ranging from mobile phones, tablet computers and video game consoles, to mainframes and supercomputers.

MICROSOFT

Cost: Windows can be expensive. Cost around $50 to $ 450 depending on the version of Windows.

Usage: On PC's desktops, laptops, servers and some phones.

File System: Ext2, Ext3, Ext4, Jfs, ReiserFS, Xfs, Btrfs, FAT, FAT32, NTFS

Developer/Company : Linus Torvalds

License: GNU/Free

Security: Linux has had about 60-100 viruses listed till date. None of them actively spreading nowadays.

Examples: Redhat, Ubuntu, Fedora, Boss, Debian, Mint

File System: FAT, FAT32, NTFS, exFAT

Developer/Company: Microsoft

License: Proprietary

Security: There have been more than 60,000 viruses in Windows. Anti Virus cost about $20 to $400.

Examples: Windows XP, Windows 7, Windows 8/8.1,

Thank you