MS - DOS Commands

A command is an instruction which is specifying an operation to be performed. In other words, MS-DOS commands are short programs that you use to talk to MS-DOS to perform certain tasks.

Types of DOS Commands
MS-DOS commands are divided into two types. They are :
1. Internal commands
2. External commands

1. Internal Commands : Internal commands are commands that are a part of the MS-DOS command interpreter. They are small routines and are stored within the COMMAND.COM file. Internal commands can be used as soon as you boot the computer i.e. you get DOS prompt (e.g. C:\>).

2. External Commands : External commands are commands that are stored on disk as program files. They are not part of COMMAND.COM file. They must be read from disk before they are executed. External commands need their own file having extension .COM or .EXE or .BAT.    

Examples of Internal commands are :
TIME, CL.S., VOL, DIR RENAME, MD, RD, PATH, DATE, VER, TYPE COPY, DEL CD, PROMPT etc.

Examples of External commands are :
Commands                File
DISKCOPY             DISKCOPY.COM
FORMAT                 FORMAT.COM
CHKDSK                 CHKDSK.EXE
EDIT                         EDIT.COM
XCOPY                    XCOPY.COM
BACKUP                 BACKUP.EXE
RESTORE               RESTORE.EXE