(Such commands which are built in are called internal commands.).DOS has something called external commands too such as FORMAT, UNDELETE, BACKUP etc.
These commands are built in with the file. DOS is basically a file called It is this file () which handles all DOS commands that you give at he DOS prompt-such as COPY, DIR, DEL etc. Let’s start by understanding what happens when we give a DOS command. Batch file programming is nothing but the Windows version of Unix Shell
