xternal commands.31

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External commands

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Objective

On completion of this period, you would be On completion of this period, you would be able to knowable to know

External commands-FORMAT, External commands-FORMAT, CHKDSK, SCANDISK etcCHKDSK, SCANDISK etc


Recap

What are internal commands?

Internal commands are built – in commands

Examples: COPY, DEL, DIR, TYPE, CD, MD, RD, MODE, PATH, DATE, TIME, COPY CON etc


Prerequisite

What is meant by commands

Instructions used to communicate with the computer system


External Commands

External commands are included in a set of programs called utility programs that are stored on a disk

When these commands are used, DOS loads appropriate utility programs from disk and then executes them

As a result, external commands are executed much more slowly than internal commands


External Commands (contd)

CHKSDK [d:] • This command is used for checking the

disk and reporting back the status of the system

• It checks for the memory and gives the detailed information about the memory consumed as well as free memory

Example :CHKDSK A:



DISKCOPY [d:] [d:]used to copy a diskette into another. This

makes the diskette in the first drive on the diskette in another drive

Example:

DISKCOPY A: B:



DISKCOMP [d:] [d:]

• Compare the contents of two diskettes on the drives specified

• If there is any difference in the contents of the disks, it gives the message

• Otherwise it asks to compare any other disks



TREE [d:] [/F]

This is used to display all the directories and subdirectories. /F displays all files if specified



PRINT: [d:] [path] filename

• This command is used for printing the contents of documents or files

• This command sends the document or the file specified to the printer for printing

ExampleC:\>PRINT D:\DOS\LETTER\MY LETTER.LET



FORMAT [d:] [\S] [\V]

• This command is used to prepare a fresh diskette to be used by the DOS for all its storage purposes

• It divides the disk into tracks and segments so that the data can be stored



• If we want to create a system diskette .i.e., a booted diskette which can be used to boot a system as it has the basic operating system in it, use ‘\S’ as option

• This \V to create a label



DEL TREE [d:] [path]

This command is used to delete the directory including all the sub directories and the files

This command has to be used carefully as it is dangerous such that it deletes all the files and subdirectories permanently



XCOPY [drive1:] pathname1 [drive2:] pathname2

It copies files and directories, including lower level directories

Where drive1 & pathname1 is the source file or directory, drive2 & pathname2 is the target file or directory

It is similar to copy command but it also copies all the subdirectories including empty directories



Example C>XCOPY A: /S

Result The above command is used to copy all

files and subdirectories on the disk in drive A to the disk in the drive C



ATTRIB [+R | -R] [+A | -A] [+S | -S] [+H | -H] [drive:] [path] [filename] [/S [/D]]It displays or changes file attributes

+ Sets an attribute- Clears an attributeR Read-only file attributeA Archive file attribute



S System file attributeH Hidden file attribute

[drive:] [path] [filename] It specifies a file for attrib to process/S Processes matching files in the current folder and all subfolders/D Processes folders as well


Summary

In this class, you have learnt about

External commands – FORMAT, CHKDSK, SCANDISK, XCOPY, ATTRIB, DISKCOPY, PRINT, TREE, DELTREE etc


Frequently Asked Questions

1. List any four DOS external commands

2. What is DOS external command?

3. Explain any four external commands in DOS.


Quiz

C>XCOPY A: /S - This command is used to copy all files and subdirectories on the disk in

a. drive A to the disk in the drive C.b. drive C to the disk in the drive A.

Answer: a


Quiz

The command used to copy a diskette into another

a. DISKCOPYb. XCOPY

Answer: a

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