External And Internal DOS commands

FORMAT Command

The external FORMAT command prepares a disk for use. If the drive is not specified, the

command uses the default drive. This command destroy all data on disk, so please backup your data before using this command.

Format c: /s

LABEL Command

The LABEL command changes the volume label or electronic name on a disk.

The volume label is stored at the beginning of the root directory and also in the master boot record.

The label is displayed at the top of the directory list that is produced by the DIR command.

The label can be up to 11 characters long and can contain spaces.

Label

CHKDSK Command

The CHKDSK command creates a status report of a disk, and it can repair lost clusters in the FAT. If you do not specify a drive, DOS uses the default drive.

CHKDSK Examines the directory, looking at the starting cluster number and the size of each file, and compares that information to the FAT.

Checks that the FAT contains the correct number of entries for each file and that there is an end-of-file marker at the end of the chain.

CHKDSK has two switches:

The /F switch tells CHKDSK to fix lost clusters, converting them to files that are

stored in the root directory under the name FILE0000.CHK (or a higher number).

The /V switch displays a list of files as it checks the directory and the FAT.

If CHKDSK finds entries in the FAT that don’t belong to a chain, or if an entry in the FAT is in more than one chain, CHKDSK reports lost allocation units or cross-linked chains.

DO NOT use CHKDSK on a hard drive if files are open. The command will mistake these

open files as being lost clusters or lost file allocation units.

SCANDISK Command

SCANDISK is a utility in later versions of DOS that is an improvement over CHKDSK.

SCANDISK checks for lost and cross-linked clusters as well as defragments the drive and

does a surface scan for bad sectors. If you don’t specify a drive, SCANDISK scans the

current drive for errors. Options of the SCANDISK command are as follows:

Use the /FRAGMENT option to defragment files on the drive.

Use /UNDO to undo the last changes that SCANDISK made.

Use /CHECKONLY to list the errors that SCANDISK finds without making any

changes.

Use /SURFACE to scan the drive for bad sectors.

There is a SCANDISK.INI file in the DOS directory that you can use to customize the

SCANDISK utility.

DEL Or ERASE Command

The DEL or ERASE command erases files or groups of files.

For example, if the default directory is A:\DOCS:

To erase all the files in the C:\TEST directory, use the following command:

ERASE C:\TEST *.*

To erase all the files in the current default directory, use the following command:

ERASE *.*

To erase the file named MYFILE.TXT in the current directory, use the following

command:

ERASE MYFILE.TXT