internal commands.29to30
TRANSCRIPT
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Objective
On completion of this period, you would be able On completion of this period, you would be able to knowto know
Conventions usedConventions used
Internal commands Internal commands
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Recap
DOS commands are divided into
Internal Commands
External Commands
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Prerequisite
What is meant by command
An instruction which is used to communicate with a computer system
We call this instruction a command
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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
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Internal Commands (contd)
Remains resident in the memory as long as the computer is on
Hence they are always available to be executed
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Convention used in Command descriptions are
[] (BRACKETS)
Items within brackets are optional
DRIVE
It refers to the drive name.
Example: C: A: B: etc
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Convention used in Command descriptions 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
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Convention used in Command descriptions are (contd)
SWITCHES
These switches control MS – DOS commands. They should always begin with a forward slash (/)
Example: /p /w etc
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Convention used in Command descriptions 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
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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
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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.
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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
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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
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Internal Commands (contd)
VOL [drive] – It displays the disk volume label which is optionally declared at the time of formatting
Example:C:\>VOL A :
ResultVolume in drive A is DBASEIIIVolume Serial Number is 0909-07BE
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Internal Commands (contd)
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
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Internal Commands (contd)
DATE [mm- dd- yy] - It displays or sets the date
Example:C>DATE
Result:Current date is FRI 21-04-07Enter the new date (mm- dd- yy): 20-04-08Now the current date will be SUN 20-04-08
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Internal Commands (contd)
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
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Internal Commands (contd)
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
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Internal Commands (contd)
Example2
C>TIME 12:07:59
C>TIME
Result
Current time is 12:07:59
Enter the new time :
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Internal Commands (contd)
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
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Internal Commands (contd)
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
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Internal Commands (contd)
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
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Internal Commands (contd)
Example2
C>DIR/W
Result
Selects wide display and lists up to files lines per line
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Internal Commands (contd)
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
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Internal Commands (contd)
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
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Internal Commands (contd)
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
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Internal Commands (contd)
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’
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Internal Commands (contd)
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
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Internal Commands (contd)
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
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Internal Commands (contd)
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
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Internal Commands (contd)
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’
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Internal Commands (contd) RMDIR/RD [drive:] path – It removes a directory
from a directory structure
ExampleC>RMDIR varsham
ResultThe above command is used to remove the
directory named varshamBefore removing the directory entirely, the
directory should be empty.
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Summary
In this class, we have learnt about
Internal commands – COPY, DEL, DIR, TYPE, CD, MD, RD, MODE, PATH, DATE, TIME, COPY CON etc.
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Frequently Asked Questions
1. List any four DOS internal commands
2. What is DOS internal command?
3. Explain any four internal commands in DOS.