What is DOS?
DOS stands for Disk Operating System. DOS controls the computer’s hardware and provides an environment for programs to run. This system program must always be present when working with our computer.
Why We Need DOS
There are a variety of reasons why we need DOS. A few of them are listed below:
DOS controls the flow of information between we and the computer (translator).
- DOS allows to store information on our computer.
- DOS allows us to retrieve information stored on our computer.
- DOS interprets and translates the software we have on our computer.
- DOS gives us access to all its function (i.e. saving, copying, and printing files).
Check the Date and Time
We can check or change the date and time once it has been set. The procedure to do this is as follows:
Directions:
- Type: date and press return.
- If the correct date is displayed, simply press return. If the date is incorrect, type the correct date and press return.
- Type: time and press return.
- If the correct time is displayed, simply press return. If the time is incorrect, type the correct time and press return.
VER Command
To see the version of DOS we use VER command.
Directions:
Type: ver and press return.
VOL Command
To see the label of the volume in the specified drive. we use VOL command.
Directions:
Type: VOL and press return.
Directory Command
The DIRECTORY command is like a table of contents in a book. This directory will list the following information:
- File names
- File extensions
- Size of each file
- Date and time the file was last updated.
Directions:
- At the C:\> type: dir and press return.
- The list of files will be shown on the screen.
NOTE: At the end of the listing, there is a line that shows the number of bytes free on the hard drive.
View a Wide Listing of Files
When we need to quickly view our files, we can add a /W to the directory command. This will display our files into five columns on the screen.
Directions:
- Type: dir/w and press return.
NOTE: Use this command when we are not concerned with looking at the file size or the date it was created.
Recall a DOS Command
The F3 function key can be used to recall the last DOS command we typed in. If we would like to retrieve a previously entered command, we can also press the up arrow key continuously until we reach the desired command we are looking for.
Check for a Single File
Instead of using the directory command to look for one particular file, we can type the name of the file after the DIR command at the C:\> prompt.
Directions:
- Type: dir format.com (filename.extension) and press return.
- The screen will display a listing of the file or a file not found message.
Check for a Group of Files
The * symbol is called wildcard and stands for any character or group of characters. This is helpful when we want to list files that start with a particular letter or group.
Directions:
- Type: dir c* and press return.
- All filenames that begin with the letter C will be listed.
Clear the Screen
When the screen get full of information, we may want to clear it. To do this, type CLS at the C:\> prompt and press return.
Create a File with DOS
Directions:
- Type: copy con first.txt and press return.
- Type the message as the following :
This is my first file.
3.Press the F6 function key (^Z) and press return.
DOS gives we a message that 1 File(s) has been copied.
Viewing The Content Of File
Directions:
- Type: Type first.txt
NOTE: We can also use the COPY command to print a file by typing: copy quick.ltr prn and press return.
Copy a File
We can use the COPY command to copy one file to another.
Directions:
- Type: copy first.txt second.txt and press return.
- DOS will tell we one file has been copied.
NOTE: Filenames cannot be more than eight characters in length. File extensions cannot be more than three characters in length.
Copy a File with a New Extension
We can also use the COPY command to copy the file with a different filename extension.
Directions:
- Type: copy first.txt second.doc and press return.
Rename a File
The RENAME command lets we rename a previous file with a new name.
Directions:
- Type: ren second.txt sec.txt and press return.
Create a Subdirectory
To create a subdirectory, we will need to use the MAKE DIRECTORY command, MD. Directions:
- Type: md info and press return.
.
Move to a Subdirectory
Once we have created a subdirectory, to move to that directory, we will use the CD command.
Directions:
- Type: cd info and press return.
Move to the Parent Directory
DOS has a quick way to move from the current directory back to the parent directory.
Directions:
- Type: cd.. and press return.
Copy a File into a Subdirectory
The COPY command lets we copy files from one directory to another.
Directions:
- Type: copy first.txt info and press return.
- TO see Type: dir info and press return.
Delete a Single File
To remove file in DOS we use the DELETEcommand, also known as DEL.
Directions:
Type : DEL first.txt and press return.
Remove a Subdirectory
To remove subdirectory in DOS we use the REMOVE DIRECTORYcommand, a.k.a. RD.
Directions:
1. Type : rd info and press return.
2. If we cannot be in the subdirectory that we wish to remove. We will need to return to the root directory (C:\> prompt).
Directions:
- Type: cd.. and press return.
- We should be back in the root directory.
- Type: rd \info and press return.
Internal vs External commands
INTERNAL COMMANDS
- These are those commands which are contained in command.com files of MS-DOS.
- These are those functions that are built into the command interpreter.
- There is no need of any external file in computer to read internal MS-DOS command.
- These commands can be used as long as DOS is running on the system. Internal commands do not vary from system to system.
- These are ver, time, del, md, cd, copy con, cls, date, vol, ren, copy etc.
EXTERNAL COMMANDS
- These are those commands which are not in-built in MS-DOS.
- External commands are those which are not included in the interpreter.
- There is a need of an internal file in the computer to read external MS-DOS command.
- External command may vary from system to system. This means any two computers with same version of MS-DOS may have same internal commands, but may have different external commands.
- These are tree, xcopy, diskcopy, more, print etc.
Diskcopy
The diskcopy allows us to copy the complete contents of a diskette to another diskette.It works only with floppy disk.
Syntax:
C:\>Diskcopy <Source Drive> <Target Drive>
Example
C:\> Diskcopy a:b:
Xcopy
The xcopy command is used to copy one or more files and/or folders from one location to another location.
Syntax:
C:\>Xcopy <Source Drive> <Target Drive>
Example
C:\> Xcopy a:b:
Switches with Xcopy
/w = We use the /w option to present a “Press any key when ready to being copying file(s)” message. The xcopy command will begin copying files as instructed after we confirm with a key press.
Example
C:\> Xcopy a:b:/w
/s = We use this option to copy directories, subdirectories, and the files contained within them, in addition to the files in the root of source. Empty folders will not be recreated.
Example
C:\> Xcopy a:b:/s
Attrib
This command is used to change the attribute of a file . By using attrib command we can make a file read only ,hide etc.
Syntax:
C:\>Attrib –r <file name>
C:\>Attrib +r <file name>
C:\>Attrib –h <file name>
C:\>Attrib +h <file name>
C:\>Attrib -a <file name>
C:\>Attrib +a <file name>
Example
c:\> Attrib-r Test.txt
Format
This command prepares a new disk for use.
Syntax:
FORMAT <DRIVE>:
Example
FORMAT B: Formats the disk in drive
FORMAT B:/s Formats the disk in drive B and transfer the DOS to it.
FORMAT B:/B Formats the disk in drive B and
reserves space for DOS.
Scandisk
This utility detects,diagnoses and repairs disk errors.
Syntax:
c:\>Scandisk
Chkdsk
This command checks the status of a selected disk.
It display several informations like:
- The total disk space.
- The total disk space occupied and the number of files.
- The amount of disk space available for use.
- The amount of memory available for use
Syntax:
c:\>chkdsk
Move
This command moves directories and files to another location on the same disk.
Syntax:
C:\>Move [Source Directory][Target Directory]
Example
c:\>move c:\Mydir\*.* c:\Newdir
Undelete
This command is used to recover files that have been previously erased.
Syntax:
C:\>Undelete <File name>
Example
C:\>Undelete Newdir
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