PROMPT

Changes the appearance of the command prompt.

Note: Usually when you see the command prompt like "C:\>", it 
should have been set by the PROMPT command like this:

PROMPT $P$G

Also, in old MS-DOS versions, the command prompt is by default 
set to "$N$G", so it is like this "C>". If you don't specify any 
parameters for PROMPT command, it will also be $N$G by default.

For more information, please refer to MS-DOS Help or Windows NT 
command line command help.