MELJUN CORTES Computer Organization Lecture Chapter14

8/13/2019 MELJUN CORTES Computer Organization Lecture Chapter14

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2007 The McGraw-Hill Companies, Inc. All rights reserved

OverviewIn this chapter, you will learn to

Explain the operation of the command-line interface

Execute fundamental commands from thecommand line

Manipulate files and folders from the command line


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Historical/Conceptual

IBM invented the PC in the late 70s but neededan operating system

Digital Research had an OS but turned them downIBM went to a small company (Bill Gates at

Microsoft) that had created BASICMicrosoft had never written an OS but acceptedthe challenge

Gates found an OS called Quick-and-Dirty-Operating-System (QDOS) and purchased it from the person who

wrote itMicrosoft released it as MS-DOS V 1.1 (Microsoft DiskOperating System)MS-DOS 6.22 ultimately released in 1994DOS used a command-line interface


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Deciphering the Command-LineInterface

IT Technician

CompTIA A+Technician


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Command-Line Interface (CLI)

How does a command-line interface work?Begins with a prompt indicating the computer is readyto do something

Type in a command and press ENTER

The command is executed

A new prompt is displayed ready for the next

commandCLI executes commands like the Windows GUI

In CLI, type the command and press ENTERIn GUI, point and click to execute commands


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Accessing the Command Line

In Windows 2000 use the Run dialog boxStart | RunType cmd

You may also access the command line throughthe Start | All Programs menu


7/39 2007 The McGraw-Hill Companies, Inc. All rights reserved

The Command Prompt

The command prompt is always focused on aspecific folder

Any commands operate on the files and folders inthe folder in which you are focusedYou must first focus on the drive and folder whereyou want to work



Filenames and File Formats

Each program or piece of data is stored as a fileon the driveFilenames have two parts

FilenameIn DOS, up to 8 characters long

ExtensionIn DOS, up to 3 characters longOptional

The filename and extension are separated by adot

Called the 8.3 naming systemThese characters may not be used/ \ [ ] | + = ; , * ?



Filenames and Formats

Windows does not restrict the filename to 8.3(can be up 255 characters)

To be backward-compatible with DOS you need tofollow the 8.3 standardWindows creates two filenames for every file toensure backward-compatibility

The extension tells the computer the type of file.exe, .doc, .xls



File Formats

All files written in binary format

American Standard Code for Information

Interchange (ASCII) used for textUniversal file formatDefines 256 8-bit characters

UnicodeUses 16-bit code to cover every character for themost common languages



ASCII Character Chart



Drives and Folders

At boot, Windows assigns partitions and a driveletter

Floppy drives are usually assigned A: or B:Hard drive partitions may be assigned C: to Z:CD-ROM drives are named after hard drives

Windows uses a hierarchical directory tree

Files are put into groups called foldersIn DOS we call folders directoriesThe root directory is at the beginning of thehierarchical structure with folders underneath



Folders and Files

Folders and files must be uniqueCant be the same name in the same folder

C:\ represents the root directory of C

To describe a subfolder, add the name of thefolder

C:\TEST

The location of a file is called the pathThe path of C:\test\file.txt is C:\test



Directory Tree


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Mastering FundamentalCommands



Structure: Syntax and Switches

The command line requires the exact syntax foreach command

Type the name of the command and desired orallowed switches

Switches modify the behavior of the command

Multiple switches may be allowable

DIR /W /PDisplays the directory in wide mode and one page

at a time



Help

Help with any command is readily available in one ofthree waysHELP gives a one-line description of each commandHELP command gives specific help for the command

Command /? gives specific help for the command



DIR Command

The DIR command lists the contents of aparticular directory

The DIR/W command lists only the filenames



DIR Command Switches



Directories: CD Command

The CD (or CHDIR) command is used to changethe focus to a different directory

The CD\ command is used to return to the rootdirectory

CD .. Goes up one directory

To switch between drives, type the drive letterfollowed by a colon

C:D:



Making and Removing Directories

The MD (or MKDIR) command is used forcreating a directory

The DEL command is used for deleting files, andthe RD (RMDIR) command is used for deletingdirectories and subdirectories

The DELTREE command is used for deletingdirectories containing files and subdirectories



Running a ProgramTo run a program:

Change the DOS focus to the directory where theprogram is stored

CD C:\Program Files\My Program

Type the filename with or without its extension andpress ENTER

Setup.exe


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Working with Files


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Working with Files Attributes (H, R, S, A) are special values assignedto a file

Hidden : hides the fileRead-only : protects a filefrom being deleted or modifiedSystem : identifies system files

Archive : identifies files thathave not been backed up

The ATTRIB.EXE program is used to inspect andchange file attributes


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Attrib Attrib can be used to change the attributes

Use + to add attribute- Use to remove attribute

Attrib +R AILOG.TXT Makes it read only

Attrib H AILOG.TXT Makes it no longer hidden


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Working with FilesWildcards :

Wildcards are special characters that enablecommands to act on more than one file at a timeThe * represents any number of charactersThe ? represents a single character

DIR *.TXT Lists all files that end in .TXTDIR *.?XT Lists all files that end in XT


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Working with FilesREN command is used to rename files

DEL and ERASE commands are used to deletefiles

COPY command is used for making a copy of thefile in a new location

MOVE command is used for moving the file to anew location

XCOPY command is used for working withmultiple directories


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Mikes Five -Step COPY/MOVE Process

1. Point the command prompt to the directorycontaining the files to be copied or movedC:\> CD \DOCS

2. Type COPY or MOVE and a spaceC:\DOCS> COPY

3. Type the name(s) of the file(s) to be copied/movedand a space

C:\DOCS> COPY *.doc

4. Type the path of the new location for the filesC:\DOCS> COPY *.doc c:\Steam

5. Press ENTER


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Working with Batch Files

Batch files are text files that store a series ofcommands

One command on each lineBatch files use the .BAT extensionBatch files may be edited with any text editor

NotepadEDIT

Batch files get their own type of icon


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EDIT

EDIT is a command-line command that starts abasic text editor


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Additional Commands

Some additional commands are

VER shows the current version of Windows

ECHO tells the batch file to put text on the screen

TYPE displays the contents of a batch file onthe screen

SET display settings that Windows has loadedby default


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ECHO Command

ECHO will display text on the screen

ECHO OFF turns off the display of text on thescreen

@ at the beginning of a line prevents displayingthe command, but not the result of the command

@ECHO OFF is frequently used in batch files toclean up the appearance when the batch file isrun


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SET and PATH Commands

SET will display the list of settings that Windowsloads by default

Programs (and batch files) are run from thelocation where the prompt is

If the program is not located in the current folder,you receive an error messageTo tell your command to look in other places, usethe PATH command

PATH by itself lists the current list of places to look fora programPATH= location; location; location; will add locations


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Beyond A+


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Using Special KeysF1 function key brings back the previouscommand one letter at a time

F3 function key brings back the entire commandat once

The DOSKEY command stores a list of all

previously typed commands and can beaccessed by using the up arrow keyType DOSKEY Windows XP/2000 automatically starts the program


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COMPACT Command

COMPACTDisplays or alters the compression state of filescompact /c


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CIPHER CommandCIPHER

Displays or alters the encryption state of files/e specifies encryption operation/a says to apply it to the files as well as the directory


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Documents

MELJUN CORTES Computer Organization Lecture Chapter14