Operating System Commands

Commands• External / internal command• In MS-DOS there are two types of commands.• An Internal command, which is a command embedded into

the command.com file, and an external command, which is not embedded into command.com and therefore requires a separate file to be used.

• For example, if your computer does not have fdisk.exe and you try using the fdisk command, you would receive an error "Bad command or file name." Fdisk is an external command that will only work if fdisk.exe, or in some cases, fdisk.com, is present.

• However, as long as MS-DOS is running on your computer internal commands such as the cd command will always be available and does not require any other files to run.

Commands• Internal command• A command that is stored in the system memory and loaded from

the command.com. • Below are examples of internal commands in MS-DOS currently

listed• Cls• Time• Type• Ver• Chdir• Copy• Date• Del• Dir ….

Commands• External command• A MS-DOS command that is not included in

command.com. • External commands are commonly external either

because they require large requirements or are not commonly used commands. Below are examples of MS-DOS external commands

• Fdisk• Find• Format• Xcopy• Ping …..

Commands