Thread: External / Internal command

What is an external / internal command?

In MS-DOS there are two kinds of commands. An Internal command, which is a command fixed into the command.com file, and an outside command, which is not fixed into command.com and consequently requires a part file to be used.

For illustration, if your computer does not have fdisk.exe and you attempt using the fdisk command, you would get an error "Bad command or file name." Fdisk is an outside command that will only work if fdisk.exe, or in some cases, fdisk.com, is there.

Though, as long as MS-DOS is running on your computer interior commands such as the cd command will always be accessible and does not need any other files to run.