One of the best sites (I think) for MS-DOS help is: http://www.computerhope.com/msdos.htm
The site gives you a complete overview of MS-DOS and it’s commands.
Some of the DOS commands I seem to use the most are:
- chkdsk (Example: chkdsk /f /r)
A utility that checks the computer’s hard disk drives’ status for any cross-linked or any additionaly errors with the hard disk drive.
- ipconfig (Example: ipconfig/renew)
A utility that displays the network settings currently assigned and given by a network.
- ftp (Example: ftp > open > domain.com > username > password > bye)
File Transfer Protocol.
- ping (Example: ping www.google.com)
A utility that helps in determining issues with networks and assists in resolving them.