Dos commands

DISK OPERATING
SYSTEM (MS DOS)
BY LECTURER SURAJ PANDEY CCT COLLEGE

WHAT IS BOOTING? TYPES OF
BOOTINGBooting: When we start our Computer then there is an operation which is
performed automatically by the Computer which is also called as Booting. In
the Booting, System will check all the hardware’s and Software’s those are
installed or Attached with the System and this will also load all the Files those
are needed for running a system.
In the Booting Process all the Files those are Stored into the ROM Chip will
also be Loaded for Running the System. After the Booting of the System this
will automatically display all the information on the System. The Instructions
those are necessary to Start the System will be read at the Time of Booting.

There are two Types of Booting
1) WarmBooting: when the System Starts from the Starting or from initial
State Means when we Starts our System this is called as warm Booting. In
the Warm Booting the System will be Started from its beginning State means
first of all, the user will press the Power Button , then this will read all the
instructions from the ROM and the Operating System will be Automatically
gets loaded into the System.
2) Cold Booting: The Cold Booting is that in which System Automatically
Starts when we are Running the System, For Example due to Light
Fluctuation the system will Automatically Restarts So that in this Chances
Damaging of system are More. and the System will no be start from its initial
State So May Some Files will be Damaged because they are not Properly
Stored into the System. BY LECTURER SURAJ PANDEY CCT COLLEGE

DISKOPERATING SYSTEM(DOS)
In the 1980s or early 1990s, the operating system that shipped with most
PCs was a version of the Disk O pe rating Syste m (DO S) created by
Microsoft: MS-DO S.
MS-DOS is a disk operating system for IBM PC–compatible computers.
In its day, it was easily the most popular operating system in the world.

As with any other operating system, its function is to oversee the operation
of the system by providing support for executing programs, controlling I/O
devices, handling errors, and providing the user interface.
MS-DOS is a disk-based, single-user, single-task operating system. These
qualities make it one of the easiest disk operating systems to understand.

The main portions of MS-DOS are the IO . SYS,
MSDO S. SYS, and CO MMAND. CO Mfiles.
IO.SYS and MSDOS.SYS are special, hidden system
files
The IO.SYS file moves the system’s basic I/O
functions into memory and then implements the MS-
DOS default control programs, referred to as device
drivers, for various hardware components.
These include the following:
The boot disk drive
The console display and keyboard
The system’s time-of-day clock
The parallel and serial communications port
DOS FILESDOS FILES

COMMAND.COM
The COMMAND.COM command interpreter accepts
commands issued through the keyboard, or other input
device, and carries them out according to the
commands definition
 When DOS runs an application, COMMAND.COM
finds the program, loads it into memory, and then gives
it control of the system. When the program is shut
down, it passes control back to the command
interpreter.

POPULAR DOS VERSIONS
MS-DOS 3
With DOS 3.0, released in summer 1984, Microsoft continued to include
additional DOS features and to support more powerful hardware. DOS 3.0
supported hard drives larger than 10MB, as well as enhanced graphics
formats.
Three revisions—3.1, 3.2, and 3.3—provided additional innovations

MS-DOS 4
By 1988 it was apparent that the wave of the future was the
graphical interface, and DOS 4 provided users with the DOS
Shell, a utility much like the Windows File Manager. Actually,
DOS Shell was simply a scaled-down version of Windows that
allowed users to manage files, run programs, and do routine
maintenance, all from a single screen. The DOS Shell even
supported a mouse.

MS-DOS 5There were several important features introduced
in the 1991 release of DOS 5.0. First of all, the
ability to load drivers into reserved (upper)
memory was a relief to those people who were
constantly running out of conventional memory.
This feature allowed more complex DOS
programs. Several software utilities made their
debut. The most commonly used utility introduced
at this time was EDIT.COM. Also added were
QBASIC.EXE, DOSKEY, UNFORMAT, and
UNDELETE.

MS-DOS 6
Released in 1993 to excellent sales, DOS 6.0
offered a number of new commands and
configurable options. Another enhancement in
DOS 6.0 was EMM386.EXE, which allowed the
system to pool extended and expanded memory.
DOS 6.0 has subsequently been revised a number
of times. As of this date, DOS 6.22 is the most
current MS-DOS version available as a stand-
alone operating system.

THE MAIN FUNCTIONS OFTHE MAIN FUNCTIONS OF
DOSDOS
DOS translate the command issued of the userin the
format that is understood by the computerto execute
it, also errormessage in the format forthe userto
understand.
Manage diskfiles,
Allocate systemresources according to the
requirement.
DOS provides features essential to control
hardware devices such as Keyboard, Screen, Disk
Devices, Printers, Modems and programs.

LOADING OF DOS
The system start-up routine of ROM runs a test called
Power On Self Test (POST) which check whether
peripherals connected to the computer are working or
not & RAM memory.
The ROM bootstrap loader attempts to read the Boot
record and if successful, passes the control on to it.
The instructions/programs in the boot record then
load the rest of the program.
The boot tries to load the DOS into the memory by
reading the two hidden files IO . SYS, MSDO S. SYS, If
these two are found, they are loaded along with the
DOS command interpreter COMMAND.COM.

4.2 COMPUTER FILES IN DOS
A file may contain a program or any other kind of
information. DOS permits the user to assign a
name consisting of two parts to a file - primary (a
maximum of eight characters consisting of
Characters, Alphabets, Number and Hyphen),
and secondary names( should consist of three
characters, which is optional) this two parts
separated by a dot (.).
Using an extension is specified, using the
complete name . Using extensions can be an
excellent way of naming a file so that it can be
identified easily.

Examples:
Filename Primary
Name
Separator Secondary
Name
Employee Employee
Employee.Exe Employee .Exe
Employee.Dbf Employee .Dbf

DOS has a way of showing which diskdrive is currently active.
The floppy disk drives are assigned alphabets A
and B, whereas the hard disk drive is assigned
the alphabet C.
Ex: If your PC includes a hard disk, besides a
FDD (Floppy Disk Drive), the drive names would
be A and C. If the prompt is A, then it implies
that the first floppy disk drive is active. Where as
the DOS prompt would be C, if the hard disk is
active. Data as well as instructions reside in a file
stored in a disk.

4.3 DIRECTORY STRUCTURE IN
DOS
Directory is just like a file folder, which contain all the logically
related files.
DOS files are organized in a hierarchical or an inverted tree-
like structure.
DOS enables the user to organize the files in a disk into
directories and sub-directories
A directory within another directory is called a sub-directory
Of course, there may be sub-directories of sub-directories,
subsub.

Levels of Directory Systems

4.4 DIRECTORY COMMAND
The directory, the user is in at any point of time, is called
the WORKING/PRESENT/CURRENT directory.
DOS indicates which directory you are in by displaying the
directory's name in the command prompt.
For example, the following command prompt indicate that
you are in the DOS directory: C:DOS>.
Knowing which directory is current helps you find files,
and to move from one directory to another more easily.
Typically, the ROOT DIRECTORY () is the initial working
directory. The entire specification of directory from root is
called a PATH. By itself, the DIR command is applicable
to the working/present directory. The names of the sub-
directories at adjacent levels are separated by backslash
(), while specifying the path to be followed while traveling
to a sub-directory.

4.5 USING PATH TO SPECIFY THE
LOCATION OF FILES
A path is the route that leads from the root
directory of a drive to the file you want to use.
Forexample , to access C:NOSLETTERNOS.LET
Where (C:) represent the drive the file is
on , 1st () is the root directory.
2 nd () separates the NOS
directory from the LETTER sub-directory .
3rd () separates the LETTER sub-
directories from the file name, NOS.LET.

There are two types of DOS command.
Internal Commands : These commands enter into the computer memory during
computer booting. These commands are not in the form of any file; so neither they can
be viewed nor can be edited or detected. For example : MD, CD, TIME, DATE, COPY,
COPR CON, TYPE ETC.
External Commands : These commands are stored in the computer list in the form of
files. These Commands can be viewed, copied, changed or deleted. For example :
FORMAT, COPY, PRINT, SYS, EDIT, TREE, SORT, PROMPT etc.
Important Internal DOS Commands
(i) MD(Make Directory) : We use this commands to make a new directory or sub
directory.
Syntax : C:>MD DIRECTORY NAME
Example : MD STUDENT
(ii) CD(Change Directory) : This commands is used to move from one directory to
another.
Syntax : C:> CD Directory name
Example : > CD Student
Exit to Directory :
CD… The command move the subdirectory to parent directory.
CD The command is used to move directly to the root directory.

(iii) RD(Remove Directory) : If a Directory which was earlier is ;not required than such
directory can be removed by using
Syntax : C:> RD Directory name
Example : >RD student
Note : (a) The directory, which is to be removed, must be empty.
(b) The directory in which one is working cannot be removed.
One has to close the directory and come to the parent directory to remove that directory.
(iv) Copy Con : Its command is used to create a file. The name of the file, which is to be
created, is written after the copy Con leaving one space in between
Syntax : Copy Con file name
To created a file, the following steps are :
(i) Type Copy Con Monu and press Enter.
(ii) Type whatever is to be typed in the file.
(iii) Press F6 function key or CTRL + Z keys ‘?Z’ will be displayed on the screen, which
indicates that the file is complete.
(iv) Press Enter and after that the DOS will save the file and will display the message ‘1
File(s) copied.

(v) Del : This command is used to erase the files which are no longer required.
Syntax : C:> Del < File name >
Example : >Del Monu
(vi) Type : This command is used to view the contents of text file.
Syntax : Type <file name>
(vii) Copy : This command is used to copy of file from one place to another place. A copy of
file is another file with the same contents.
Syntax : C:1> copy <source> < destination path>
(viii) Ren : This command is used to rename the file. In REN command two parameters are
used. The first is the file we want to rename and the second is the new name for the file.
Syntax : > Ren <old file name> <New file name>
(ix) DIR: This command is used to display of directory and files.
Syntax : C:> DIR ?
(x) CLS : This command is used to clear the screen.
Syntax : C:> CLS

TYPE
This command is used to display the contents of a text file or files. The
syntax is: TYPE [drive:][path]filename
Now, lets try to display the contents of the file named filename we’ve created
earlier using COPY CON command.

Most Commonly Used External DOS Commands
EDIT
This command is used to modify or change the data of a file.
Syntax is EDIT  [/B]  [/H]  [/R]  [/S]  [filename(s)]
Using switch /B you can force the edit in monochrome mode. /H displays the
maximum number of lines possible for your system hardware. Whereas using /R
and /S one can load files in read-only mode and force the use of short filenames
respectively. [filename(s)] is used to specify file(s) to go edit. You can use
wildcards (* and ?) to specify multiple files.
LABEL
It is used to create, change, or delete the volume label of a disk.
Syntax is LABEL    [drive:]  [label]
LABEL  [/MP]   [volume]   [label]
Here, [drive:] is for secifying the drive letter of a drive to be labelled and [label]
specifies the label of the volume disk. [/MP] is used to specify that the volume
should be created as a mount point and [volume] is used to specify volume
name, usually mentioned after drive letter followed by colon and then giving
volume name required. BY LECTURER SURAJ PANDEY CCT COLLEGE

DISKCOPY
This command copies the contents of one floppy from the source drive to a
formatted or un-formatted floppy disk in the destination drive. This command
copies the data from particular position on the source disk to exactly the same
position on the destination disk. Syntax Diskcopy A: B:
copies contents of A: to B: drive. This command can be used with /V switch
which verifies that the disk is copied correctly.
CHKDSK
This command is used to check a disk and display a status report with
properties of disk like serial number, volume label, memory and other properties
along with errors on the disk if any.
Syntax is CHKDSK [volume path] [/F] [/V] [/R] [/X] [/I] [/C]
[/L[:size]]
TREE
This command is very useful to view the list of directories and subdirectories
present on the disk in graphical form. If you wanted to include files also with
directories and subdirectories, then you’ll have to give the command line as
tree/f which presents the tree view of all the content on your disk. Here is the
syntax for this command with allowed switches: BY LECTURER SURAJ PANDEY CCT COLLEGE

TREE [drive:path] [/F] [/A]
In case you wanted use ASCII instead of extended characters, then go ahead
include /A in the command line.
DELTREE
This command is used to remove a directory along with its contents.
Syntax is deltree [drive:path]
here, [drive:path] specifies the directory name to be deleted. All the
subdirectories and files in this directory will be deleted without prompt and there’s
not getting back. So, keep caution while using this command.

FORMAT
This command creates a new root directory and a File Allocation Table (FAT) for
the disk. In order for MS-DOS to be able to use a new disk you must use this
command to format the disk.
FORMAT with /S switch
When the disk is formatted with /s option, the disk can be used as a booting
disk. C:>DOS>Format A: /s
The above command copies the OS files MSDOS.SYS, IO.SYS and
COMMAND.COM which are required for booting the machine from your system
startup drive to the newly formatted disk. The disk can then be used for booting.
FORMAT with /U switch
Here’s the command C:DOS>Format A: /U
This command specifies an Unconditional Format which destroys all existing
data and prevents you from later unformatting the disk.
FORMAT with /Q switch
This can be used only with the previously formatted disk. This deletes FAT, Root
directory and data of disk but doesn’t scan for the bad errors. This is generallyBY LECTURER SURAJ PANDEY CCT COLLEGE

BACKUP
The Backup command backs up one or more files from one disk to another. You
can backup files onto either a hard disk or on a floppy disk. Syntax is
BACKUP Source Destination
Here source specifies the location of files to be backed up and destination drive
specifies the drive on which you want to store the backup files. The backed-up
files are stored in backup.nnn and control.nnn files where nnn represents the
backup disk number.
Backup with Switches
The /S switch can be used to backup the contents of all files in the source
including the contents of sub-directories.
The /N switch can be used to backup only those files that have changed since
the last backup.
Backup command with /D:mm-dd-yyyy switch will backup files that have
changed since the data specified.

RESTORE
The RESTORE command restores files that were backed up by using
BACKUP command. Syntax: RESTORE drive1 drive2:path
Here drive1 specifies the drive on which backup files are stored.
drive2:path specifies the path to which those backup files will be restored.
► Using backup command with /S switch is used to restore all backup files
to their original directories and sub-directories.

1. MORE:-Using TYPE command we can see the content of any file. But if length of file is greater than 25 lines then
remaining lines will scroll up. To overcome through this problem we uses MORE command. Using this command we can
pause the display after each 25 lines.
Syntax:- C:> TYPE <File name> | MORE
C:> TYPE ROSE.TXT | MORE
or
C:> DIR | MORE
2. MEM:-This command displays free and used amount of memory in the computer.
Syntax:- C:> MEM
the computer will display the amount of memory.
3. SYS:- This command is used for copy system files to any disk. The disk having system files are known as Bootable Disk,
which are used for booting the computer.
Syntax:- C:> SYS [Drive name]
C:> SYS A:
System files transferred
This command will transfer the three main system files COMMAND.COM, IO.SYS, MSDOS.SYS to the floppy disk.

4. XCOPY:- When we need to copy a directory instant of a file from one location to another the we uses xcopy command.
This command is much faster than copy command.
Syntax:- C:> XCOPY < Source dirname > <Target dirname>
C:> XCOPY TC TURBOC
5. MOVE:- Move command is used for moving one file or multiple files from one location to another location or from one
disk to another disk.
Syntax:- C:> MOVE <file name> <path name>
C:SONGS> MOVE *.MP3 C: SONGSOLD SONGS
C:>
6. FC:-(File Compare) This command is capable for comparing two set of files and display difference between two files.
Syntax:- C:> FC <First set of file> <Second set of file>
C:> FC ROSE.TXT GULAB.TXT
7.CHKDSK:-(Check disk) - This command is used to check the status of a disk and show the report of result status.
Syntax:- C:> CHKDSK

8. SORT:- This command is useful when we want to sort a file. When we run this command the result can be get to
display device or file.
Syntax:- C:> SORT /R < Input file name> <output file name>
Suppose we have a file Player.txt which having the list of a cricket player team and we want to sort the list
of players, then we uses this command
C:> SORT Player.txt
If we not specify the output file name then result will show to the screen.
/R- switch is used for sorting the file in descending order like from Z to A or from 9 to 0.
9. FIND:- The FIND command is used to search a file for a text string.
Syntax:- C:> FIND "String to search" <File name>
C:TEST>find "office" gulab.txt
---------- gulab.txt
A clock in a office can never get stolen
10. DISKCOPY:- DISKCOPY copies the contents of a floppy disk to another.
Syntax:- C:> DISKCOPY <Drive1> <Drive2>
C:> DISKCOPY A: B:
This command will be copy all contents of A drive to B drive. BY LECTURER SURAJ PANDEY CCT COLLEGE

11. ATTRIB:- Sets the various type of attribute to a file. Like Read only, Archive, Hidden and System
attribute.
Syntax:- C:> ATTRIB [± r] [± a] [± h] [± s] <File name>
here r - for read only, a- for archive, h - for hidden, s - for hidden attribute.
C:> ATTRIB +r Gulab.txt
This command will change the attribute of file gulab.txt to read only mode. To remove the read only attribute we will follow this command.
C:> ATTRIB -r Gulab.txt
12. LABEL:- If you are not happy with the volume label of hard disk, you can change it.
Syntax:- C:> LABEL
C:>LABEL
Volume in drive C is JAI
Volume Serial Number is 3E42-1907
Volume label (11 characters, ENTER for none)? INFOWAY

FORMAT:- This command creates new Track & Sectors in a disk. Every
Syntax:- C:> FORMAT [drive name] [/S]
C:> FORMAT A:
this command will create new track & sectors.
C:> FORMAT A: /S
This command will transfer system files after formatting the disk.

Dos commands

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Dos commands