Internal commands.29to30

Internal commands

http://improvec.blogspot.in/
1

Objective

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

Conventions used

Internal commands

2

Recap

DOS commands are divided into

Internal Commands

External Commands

3

Prerequisite

What is meant by command

An instruction which is used to
communicate with a computer system

We call this instruction a command

4

Internal Commands

 Internal commands are built–in commands

 These commands are in COMMAND.COM
program

 This program is loaded with the operating
system into the memory during booting

5

Internal Commands (contd)

 Remains resident in the memory as long as
the computer is on

 Hence they are always available to be
executed

6

Convention used in Command descriptions
are

 [] (BRACKETS)
Items within brackets are optional

 DRIVE
It refers to the drive name.
Example: C: A: B: etc

7

are (contd)
 PATH
It refers to a directory name
Syntax :[drive_directory] [directory…] directory

 PATHNAME
It mentions the files that are to be referred in
the path. It is used to locate a file
Syntax : [drive_directory] [directory…] filename

8

are (contd)
 SWITCHES

These switches control MS – DOS
commands. They should always begin with a
forward slash (/)

Example: /p /w etc

9

are (contd)
 WILDCARDS

If we want to carry out a task for a group of
files whose names have something in common,
we can use wildcard characters to specify
groups of files

10

Wild characters
DOS recognizes two wildcard characters

 Asterisk(*) – represents one or more characters
that a group of files has in common

 Question mark(?) – represents a single
character that a group of files has in common

11

Examples of wildcards
 *.txt : All files with .txt extension
Examples are letter.txt, july.txt, and message.txt

 report.* - All files named report with any
extension.
Examples: report.txt, report.let and report.wri.

12

Examples of wildcards (contd)

 M*.* : All files beginning with the letter M
regardless of extension.
Example are march.xls, memo.txt and
madhavi.lvu

 ???.* : all files having 3 or less characters with
or without any extensions.
Examples are sun.bmp, son.bm and ab.x

13

Internal Commands

 CLS- Clears the screen, takes the cursor to the
top left and the system Prompt appears at top
left

 VER – It displays the MS-DOS version

 DEL/ERASE [drive:] pathname – It deletes the
specified file or files. The wildcards (* and ?) can
be used with del command to delete more than
one file at a time
14


 VOL [drive] – It displays the disk volume label
which is optionally declared at the time of
formatting

Example:
C:>VOL A :

Result
Volume in drive A is DBASEIII
Volume Serial Number is 0909-07BE
15


 PROMPT [[text] [$character]…] – It changes the
MS-DOS command prompt. $ character prompts
are below

$t Current time $l <
$d Current date $q =
$n Drive letter $$ $
$p Directory $e Escape
$v Version number $g >
$h Backspace
$_ Return-Linefeed
16


 DATE [mm- dd- yy] - It displays or sets the date

Example:
C>DATE

Result:
Current date is FRI 21-04-07
Enter the new date (mm- dd- yy): 20-04-08
Now the current date will be SUN 20-04-08

17


 TIME [hours : minutes : seconds . Hundredths]

It allows to enter or change the time of the
system and see the current time

To type a new time, the valid values are hours is
0-23, minutes is 0-59, seconds is 0-59 and
hundredths of seconds 0-99

18


Example1
C>TIME

Result
Current time is 1:28:40.51
Enter the new time : 11:07:51.21
Now the current time will be ’11:07:51.21

19


Example2
C>TIME 12:07:59
C>TIME

Result
Current time is 12:07:59
Enter the new time :

20


 PATH [drive:] [path] [;[drive:] [path]…]

It sets a command search path for programs not
in the current directory

The above command is used to search more
than one path by specifying several paths
separated by semicolons
21


 DIR [drive:] [pathname] [/p] [/w] – To list the files
in a directory. Wildcards can also be used with
Dir command

Example1
C>DIR

Result
Volume in drive C is DOS400
22


Directory of C:vinay
. <dir> 1-11-90 1:05
.. <dir> 1-09-90 13:05
BASIC EXE 67520 19-12-90 2:13
BUDGET BAS 814 1-01-91 1:45
FINAN90 BAS 3456 7-07-90 7:34
5 File (s) 4329472 bytes free

23


Example2
C>DIR/W

Result
Selects wide display and lists up to files lines
per line

24


Example3
C>DIR/P

Result
Selects page mode and makes the directory
display to pause once the screen is filled
To resume scrolling the display any key can
be pressed

25


 TYPE [drive] filename – It displays the contents
of a text file on the screen

Example:
C>TYPE message.dat>PRN

Result
It sends the contents of file “message.dat” to
the printer
26


 COPY [drive:] [pathname] [drive:] [pathnamr2] –
It copies one or more files to another location

COPY pathname1 + pathname2 […]pathname..
It appends the files. Wildcards can also be used
with copy command

27


Example1
C>copy bpay.rpt basicpay.rpt

Result
It copies a file named ‘bpay.rpt’ in the same
drive as
another name called ‘basicpay.rpt’

28


Example2
C>copy BPAY.RPT A:PROLL.RPT

Result
It copies a file bpay.rpt from current drive C
to drive A named as proll.rpt

29


Example3
C>COPY *.rpt + ref.txt summary.doc

Result
the above copy command combines all *.rpt
files and ref.txt files and stores in filename called
summary.doc

30


 MKDIR/MD [drive:] path – This command
creates required directory

Example
C>MKDIR letters

Result
It the above example, the command is used
to create a directory named letters
31


 CHDIR/CD [path] – It changes the current
directory for the specified directory

Example
C>CHDIR division

Result
The above command changes the working
directory to the directory called ‘division’
32

 RMDIR/RD [drive:] path – It removes a directory
from a directory structure

Example
C>RMDIR varsham

Result
The above command is used to remove the
directory named varsham
Before removing the directory entirely, the
directory should be empty.

33

Summary

In this class, we have learnt about

Internal commands – COPY, DEL,
DIR, TYPE, CD, MD, RD, MODE,
PATH, DATE, TIME, COPY CON etc.

34

Frequently Asked Questions

1. List any four DOS internal commands

2. What is DOS internal command?

3. Explain any four internal commands in DOS.

35

Quiz

 Internal commands are _________
Answer: built in commands

36

Quiz

 The instructions which are used to communicate
with the computer system
a. instructions
b. commands
Answer: b

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Internal commands.29to30

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Internal commands.29to30