Explain Three Parts Of The DOS Commands.

A command is set of instructions that are used to perform a specific task. The DOS has different types of command for different tasks. Each DOS commands consist of three parts. These parts are Command Name, Parameters and switches. Command names indicated the function of the command. For example command CLS clears the computer screen. Some commands consist of only command name such as CLS, VER etc.

Sometimes parameters are used with DOS commands. Parameters are the guidelines for DOS commands. A Parameter indicates certain actions of the commands. For example DEL command requires parameter for example file name to be deleted. Some commands require more than one parameter, for example rename the file, names of two files are given, source file and target file etc. such as REN letter. tex memo. tex.

In some commands, parameters are optional. For example DIR command can be used without parameters. Switches indicate how the command is to be carried out. For example listing of files and subdirectories page wise in the root directory that contains a large number of files, the P switch is used with DIR command. For example DIR/P. Here P stands for page wise.

Every DOS Command has the following Parts

Path, Command, Additional options

Path: The path is the option part of the command and is not necessary to use. This portion specifies the location of the DOS Command. For internal command of the DOS the path is not used, because all the internal DOS commands are already presented in the memory. The command interpreter does not need to locate it. External commands are not present in memory. They need to specify location but if the file is to be used where it is present then we do not need to specify it. For example, we want to use DIR command. This is an internal command. We don't need to specify path. If we want to use an external command and it is on C:\temp and we want to use it in d:\work then we need to use this as D:\work> c:\temp\test.exe

Command: This is the name of the command. For example DIR, RENAME, FORMAT and etc.

Additional Options: Almost all the DOS commands have switches for additional options. DIR has /w, if we want to get director width wise. These options enhance the use of DOS commands and sometime are necessary to give these switches. In FORMAT command the switch is mandatory.