MS-DOS was and is still somewhat useful, though it has since pretty much outlived its usefullness. I got a reintroduction to DOS when I was adding content to an old Windows 95/3.1 game by Crack Dot Com called Abuse. Good game. Find it here:
http://www.rocket-surgery.net/abuse/downloads.html
PS: Is there any way DOS could be used as a bot code editor?