Computer Systems Week 11: The Command Line Interface Alma Whitfield

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

3 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

4 Organising files Thousands of files can be held in secondary storage Organising the files is a job for the operating system

5 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

6 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

7 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

8 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

9 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

10 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

11 Entering MS-DOS commands Commands consist of A single word Optional extra information e.g. c:\>ver c:\>ping c:\>ping

12 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

13 Finding out what is in the current directory Use the dir command E.g. c:\>dir

14 Disc information

15 Directory name

16 Information about the files in this directory

17 Date and time file last changed p = pm a = am

18 indicates these two items are directories

19 This file is named win2k.xpr It is 189,624 bytes in size

20 Total size of files in this directory Number of bytes still available on the disc

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

22 File handling in MS-DOS Create 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

23 Using edit Demo Creating text files Editing text files

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

25 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

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

27 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>

28 Batch files Collecting batches of commands into one command Like a macro in other applications e.g. Word, Excel

29 A batch file example What directory structure does this batch file create: cd \ md A md B cd A md C

30 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

31 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

32 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

33 Operating systems: early 1980s

34 Operating systems Microsoft Windows family of operating systems Windows Windows 95 Windows 98 Windows 2000 Windows XP Vista

35

36 A brief survey of Microsoft Windows Operating Systems Also - flv file present locally

37 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

38 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