Unix Ppt 3892

8/2/2019 Unix Ppt 3892

1/51

Operating Systems

The RelationshipBetween Hardware &Software

8/2/2019 Unix Ppt 3892

2/51

Goals

Understand what an operating system is

Become familiar with several different operating systems

Learn about the important features of an operating system,including file management

Understand the Unix Operating System and tools associatedwith Unix

Understand Unix Permissions

8/2/2019 Unix Ppt 3892

3/51

Why Study Operating Systems?

Understand therelationship betweenhardware & software

Understand futureOperating Systems

Understand powerfultools to help you in yourcomputer use

8/2/2019 Unix Ppt 3892

4/51

What is an Operating System?

Software

Controls the relationshipbetween all othersoftware and hardware

Other Roles

8/2/2019 Unix Ppt 3892

5/51

The Two Major Types of OSs

Letters with symbols, such asC:\>

Type what you want thecomputer to do - theCOMMAND

Type it correctly DOS and UNIX, but they do

have GUIs available

Pictures with descriptivewords

Click a picture to start aprogram

Point and Click

Much easier to move thepointer with the mouse andCLICK on a picture, than toremember COMMANDS

Window 3.1, Windows 95, MACO/S
http://klingon.cs.iupui.edu/~micenogl/os9a.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9b.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9c.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9d.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9e.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9e.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9e.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9e.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9d.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9c.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9b.htmlhttp://klingon.cs.iupui.edu/~micenogl/os9a.html

8/2/2019 Unix Ppt 3892

6/51

So, What Does an OS Do?

Controls the INPUT,OUTPUT, and PROCESSING

activities for the computer It is the BOSS of what

happens in the S/W, the H/W,and between the S/W andH/W

High-quality O/S can make

your computer more effectiveand efficient

Good OS makes thecomputer easier to use andmore efficient

8/2/2019 Unix Ppt 3892

7/51

The Roles of an Operating System

A Traffic Cop

A CommunicationSystem

A Box of Tools

A Self-Starter

8/2/2019 Unix Ppt 3892

8/51

OS as a Traffic Cop

Controls the resourcesof the computer

Resources include:memory, file storage,and CPU

Multitasking is possible

on new computers

8/2/2019 Unix Ppt 3892

9/51

OS as a Communications System

Helps all of theHARDWARE

componentscommunicate with eachother

Helps the software

communicate with thehardware

8/2/2019 Unix Ppt 3892

10/51

OS as Toolbox

Several utility programsincluded with an O/S

File Management

Memory Management

AppearanceManagement

Networking Tools

8/2/2019 Unix Ppt 3892

11/51

OS as a Self-Starter

Takes over just afterbooting

Checks to see allhardware is present

Mechanisms for HardBoot & Soft Boot

8/2/2019 Unix Ppt 3892

12/51

Flavors of Operating Systems

Marketed by Microsoft in 1981

Command-Line

Inspired by UNIX

Used on computers with the Intel Chip

DOS

8/2/2019 Unix Ppt 3892

13/51


Developed by Apple in 1984

Successful Marketing Campaign

Changed the ideas about ease of use

Largely ignored by the PC world

Apple Macintosh

8/2/2019 Unix Ppt 3892

14/51

The 1984 Macintosh Ad

Premiered during 1984Superbowl

Played just once

Launched a new era ofadvertising

8/2/2019 Unix Ppt 3892

15/51


Developed in 1992

First commercially successful GUI for PCs

Actually not an Operating System

Technically a shell that runs on top of DOS

Windows 3.1

8/2/2019 Unix Ppt 3892

16/51


Developed in 1995

Introduced the idea of the desktop for PCs

Independent Operating System

Made networking easier

Windows 95/98/2000

8/2/2019 Unix Ppt 3892

17/51


Developed in 1995

Introduced the idea of the desktop for PCs

Independent Operating System

Made networking easier

Windows 95/98/2000

8/2/2019 Unix Ppt 3892

18/51


Developed by Bell Labs in 1969

Command-Line OS

Offered File Sharing

Offered Process-Sharing

Unix

8/2/2019 Unix Ppt 3892

19/51

Introducing Unix Commands

Command Line OS

Issue commands from a command prompt:phoenix{jstudent}/:

Unix is case sensitive

Commands are typed in lowercase:cp (copy) is NOT the same as Cp or CP

8/2/2019 Unix Ppt 3892

20/51

Unix Shells

Unix has a number of shells which help the userinteract with the Operating System Kernel (the main

program that stays resident in memory and executesOS commands)

Shell Examples: Bourne Shell

Korn

Bash

TCSH

CshC-shell The default shell for Phoenix

8/2/2019 Unix Ppt 3892

21/51

Command Syntax

Case sensitive! All commands are lowercase

General Format:command [switches] parameter1 parameter2

Example:ls l *.html

Command

FlagArgument

8/2/2019 Unix Ppt 3892

22/51

Correcting Typographical Errors

DEL key removes the character to the left (in

some Telnet clients, BACKSPACE will also dothis)

To erase:

C-w Erases previous word

C-u Erases an entire line

8/2/2019 Unix Ppt 3892

23/51

Directory Structures

Unix paths begin with a forward slash

The initial forward slash (/) represents the rootdirectory

An absolute path begins at the root:/home/jstudent/public_html/

A relative path indicates location relativetoyour present working directory:../images/

8/2/2019 Unix Ppt 3892

24/51

More on Directories

The command pwd will return the directory

name in which you are currently working The directory that represents your personal

section of the server is called your homedirectory

The root directory is parent directory to allother directories (usually restricted use)

8/2/2019 Unix Ppt 3892

25/51

Directory Notation

/ - represents a directory

/. represents the current directory

/.. represents the parent directory

/~ - represents a users home directory

Creating directories

No spaces in a name Use _ or camel casing to name directories

Case sensitive (usually in lowercase, with camel casing)

8/2/2019 Unix Ppt 3892

26/51

Creating a Directory

Use the mkdir command:mkdir campingImages

Command

Required argument:name of the directory(uses camel casing)

8/2/2019 Unix Ppt 3892

27/51

Naming Files

Extensions

Determine the type of the file

Examples

*.txt

*.html

*.cgi

*.gif

*.jpg

Filenames that begin with . are hidden and will not

appear unless a special directory command is used.

8/2/2019 Unix Ppt 3892

28/51

File & Directory Permissions

ls l command will show full details:drwxr-xr-x 2 rmolnar staff 512 Sep 18 2001 funstuff/

-rwxr-xr-x 2 rmolnar staff 312 Oct 11 2000 new.html

Permissions

Owner

Group

Size

Date

Name

8/2/2019 Unix Ppt 3892

29/51

Unix Permissions

Permission sequence found at the beginning ofa directory listing (first 10 characters):

d rwx r-x r-x

Directory

?

Owners

Permissions

Groups

Permissions

Worlds

Permissions

8/2/2019 Unix Ppt 3892

30/51

Unix Permissions

The first character represents whether thelisting is a directory. If it is a directory, a d will

appear in the first character; otherwise, youshould normally see a dash (-).

d rwx r-x r-x

8/2/2019 Unix Ppt 3892

31/51

Unix Permissions

The remaining nine characters are divided intothree triplets, each representing thepermissions for the owner, the owners group

and the world.

- rwx r-x r-x

Owner

Group

World

8/2/2019 Unix Ppt 3892

32/51

Unix Permissions

In each triplet, three permissions can beassigned: 1st Position: r stands for Read; grants permission

to view the contents of a file or directory (Value is ror -)

2nd Position: w stands for Write; grants permission

to modify a file or the contents of a directory (Valueis w or -)

3rd Position: x stands for eXecute; grants permissionto run an application or open a directory (Value is xor -)

8/2/2019 Unix Ppt 3892

33/51

Unix Permissions

When changing permissions, we must first decide whatnumber will represent the permissions for a triplet

We can do this by determining whether or not apermission is turned on or off If a permission is turned on (represented by r, w, or x), it gets

a value of 1

If a permission is turned off (represented by a dash), it gets a

value of 0 After deciding whether the three permissions in a triplet

are on or off, we will have a binary number

We can convert the binary number to its octalequivalent

8/2/2019 Unix Ppt 3892

34/51

Unix Permissions

Permissions Binary Octal

- - - 0 0 0 0

- - x 0 0 1 1

- w - 0 1 0 2

- w x 0 1 1 3

r - - 1 0 0 4r x 1 0 1 5

r w - 1 1 0 6

r w x 1 1 1 7

8/2/2019 Unix Ppt 3892

35/51

Unix Permissions

Once youve established the octal number representingthe permission for each triplet, you can then use the

change mode (chmod) command to give a directory orfile proper permissions

Syntax:chmod permissionMask file/directory

Example:chmod 755 public_html

Typically, directories and executable files are given755 permissions, while other files are given 644permissions

8/2/2019 Unix Ppt 3892

36/51

Navigating Unix

To move from directory todirectory, we use the cd

command Syntax:

cd path/

To move from a parent to achild directory:

cd child/ To move from a parent to a

grandchild directory:cd child/grandchild

Grandchild Directory

Child Directory

Parent Directory

8/2/2019 Unix Ppt 3892

37/51

Navigating Unix

To move from a child toa parent directory:

cd .. To move from a

grandchild to a parentdirectory:cd ../..

To move to a directorythat shares the sameparent:cd ../Child 2

Grandchild Directory

Child Directory

Parent Directory

Child 1 Directory Child 2 Directory

Parent Directory

8/2/2019 Unix Ppt 3892

38/51

The List Command

The list command (ls) shows the contents of adirectory

We can add switches to the list command to modifywhat the command can do: ls lshows files in long format, including permissions (On

Phoenix, you can also use the aliasll)

ls ashows hidden files

lscshows file listings in a column format

ls tsorts file listings by last modified date

To use more than one flag, concatenate them:ls -lt

8/2/2019 Unix Ppt 3892

39/51

Using Wildcards with ls

ls a* - Wildcard, All files starting with 'a'

ls *a* - All filenames with 'a' in them

ls *a*html - All filenames with 'a' in them and

ending with html

ls ????? - All 5 charater filenames

ls [abc]*- All filenames starting with a, b, or c

ls [a-c]* - Same as above but done as a range

ls [^a-c]* - All filenames not starting with a, b, or c

8/2/2019 Unix Ppt 3892

40/51

The Unix Copy Command

cp can be used to make a copy of a file,

leaving the original file untouched

Syntax:cp oldfile [path/]newfile

To make a copy of a file while both the original

and copy are in the samedirectory:cp index.html home.html

8/2/2019 Unix Ppt 3892

41/51

The Unix Copy Command

To make a copy of a file that results in the copyretaining the originals name, but is housed in adifferent directory:cp index.html ../academic/

To make a copy of a file that results in the copy

having a new nameand is housed in a differentdirectory:cp index.html ../academic/home.html

8/2/2019 Unix Ppt 3892

42/51

The Unix Move Command

Themv command has two purposes:

To move files from one directory to another

To rename files

Syntax:mv oldfile newpath/[newfilename]

To move a file from one directory to another:mv index.html ../friends/

8/2/2019 Unix Ppt 3892

43/51

The Unix Move Command

To rename a file (stays in the same directory):mv index.html home.html

To move a file andrename it at the same time:mv index.html ../friends/home.html

8/2/2019 Unix Ppt 3892

44/51

Deleting Files

Use rmto delete files

Syntax:rm filename

To delete a single file:rm index.html

(answer Y to confirm delete)

To delete multiple files using a wildcard:rm *.html(answer Y to confirm delete for each file)

8/2/2019 Unix Ppt 3892

45/51

Deleting Directories

Use rmdir to delete directories

DIRECTORY MUST BE EMPTY!!!!

Syntax:rmdir directoryname

To delete a directory:

rmdir images/(answer Y to confirm delete)

8/2/2019 Unix Ppt 3892

46/51

Other Useful Commands

passwd Password utility that allows users toupdate their passwords

exit End your Unix session (you can alsousebye on Phoenix)

clear Gives you a blank screen (you canalso use cls on Phoenix)

who Lists users currently logged in to theserver

8/2/2019 Unix Ppt 3892

47/51


finger username Retrieves informationabout a user

cal Displays a calendar of the currentmonth

date Displays the current system date

!! (pronounced bang bang) repeats thelast command

![a..z] Repeats the last commandbeginning with selected letter (a-z)

8/2/2019 Unix Ppt 3892

48/51


|more Added to commands which displaylists to force page stops (Ex: ls lt |more)

C-z Temporarily stop a process

fg Bring a process to the foreground after ithas been stopped

vacation Turn on the autoreply for e-mailpine Launch the Pine E-mail client

emacs Start the Emacs editor

8/2/2019 Unix Ppt 3892

49/51

Online Manual

Eight Sections Commands

System calls

Library functions

Devices and device drivers

File formats

Games

Miscellaneous

System maintenance

8/2/2019 Unix Ppt 3892

50/51

Usingman

man command

To lookup help on the cp command:man cp

To lookup help on the ls command:man ls

C-c exits the manual.

8/2/2019 Unix Ppt 3892

51/51

Questions?

Documents

Unix Ppt 3892