Computer Systems

2009-2010

Week 11: The Command Line Interface

Alma Whitfield

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What we have done so far Files organised into directories Directories form a hierarchy Manipulated files using Windows

Windows Explorer

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What we are going to do today Examine the MS-DOS operating

system’s command line interface

Look at how MS Windows has developed from MS-DOS

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Organising files Thousands of files can be held in

secondary storage Organising the files is a job for the

operating system

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Operating systems An operating system is software

installed on the computer to make it possible to use it without needing a degree in electronic engineering

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Operating systems: mini-history Early machines had no operating

system – you needed to be an engineer to run a program Could only run one program at a time The CPU spent most of its time waiting

for hardware to complete tasks like printing or writing to or reading from disc

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Operating systems: mini-history By the 1960s, operating systems

could run several programs at the same time While one program is waiting for a read

from disc, another could be executing

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Operating systems: early 1980s Microsoft introduced PC operating

system called MS-DOS Microsoft Disc Operating System Disc operating system means file

organisation Instructions typed in at a command

line

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Operating systems: early 1980s Microsoft introduced PC operating

system called MS-DOS Microsoft Disc Operating System Disc operating system means file

organisation Instructions typed in at a command

line

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MS-DOS uses a Command Line Interface Do not use mouse Type in commands as words

i.e. lines of command Use a Command Prompt box

Start | Programs | Accessories | Command

Prompt Demo

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Entering MS-DOS commands Commands consist of

A single word Optional extra information e.g. c:\>ver

c:\>ping www.playboy.com

c:\>ping www.bbc.co.uk

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The current directory When using MS-DOS, it always places you

in a directory “Everybody has got to be somewhere” (Eccles

– the Goon Show – circa 1954) This is called the Current Directory The command prompt tells you what the

current directory is E.g. c:\windows\temp> …. means current directory is \windows\temp

on the c: drive

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Finding out what is in the current directory Use the dir command

E.g. c:\>dir

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Disc information

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Directory name

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Information about the files

in this directory

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Date and time file last changedp = pma = am

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<DIR> indicates these two items are directories

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This file is named win2k.xprIt is 189,624 bytes in size

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Total size of files in this directoryNumber of bytes still available on

the disc

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Changing drive in MS-DOS Demo Use drive name (A:, C: etc)

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File handling in MS-DOSCreate and edit text files edit

Display text files type

Change current directory cd

Make a new directory md

Remove a directory rd

Copy files from one directory to another directory

copy

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Using edit Demo Creating text files Editing text files

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Using copy Demo Using wildcards in copying c:\>copy *.txt c:\temp c:\>copy *.* c:\temp

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Using md to make directories Demo Building this directory structure c:\>md D c:\>md A c:\>cd D c:\D>md B c:\D>cd \ c:\>cd A c:\A>md D

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Using cd Demo Moving up one level c:\>cd A c:\A> c:\A>cd .. c:\>

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Using cd with absolute and relative paths Absolute path:

starts with root c:\>cd \A\D c:\A\D> Relative path: starts

from current directory

c:\A\D>cd ..\..\D c:\D>

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Batch files Batch files Collecting batches of commands

into one command Like a macro in other applications

e.g. Word, Excel

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A batch file example What directory

structure does this batch file create:

cd \

md A

md B

cd A

md C

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A second batch file example Write a batch file to

create this directory structure: cd \

md A

md B

md C

cd B

md D

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A third batch file example Write a batch file to

create this directory structure: cd \

md D

md A

cd D

md B

cd \A

md D

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Operating systems: early 1980s Apple Inc introduced first operating

system with a Graphical User Interface (GUI) Apple Lisa Apple MacIntosh Instructions issued using mouse clicks

on menus, and buttons

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Operating systems: early 1980s

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Operating systemsMicrosoft Windows family of operating

systems Windows Windows 95 Windows 98 Windows 2000 Windows XP Vista

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A brief survey of Microsoft Windows Operating Systems http://www.youtube.com/watch?v=y48rthTbrA8

Also - flv file present locally

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Microsoft Windows has two streams Graphical front end to MS-DOS

Windows Windows 95 Windows 98

Not based on MS-DOS Windows 2000 Windows XP Vista

Streams look the same but completely different inside

A brief survey of Microsoft Windows Operating Systems

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Other PC Operating Systems Linux operating systems

Red Hat Linux SuSE Linux Mandrakesoft Linux etc

Competitor to Microsoft Based on Unix operating systems Originally had only command line

type interfaces Recent developments provide

graphical front ends