$$ (Comment Specifier)
If two dollar signs ( $$ ) appear at the start of a command, then the rest of the line is treated as a comment, unless the comment is terminated by a semicolon.
$$ [any text]
The $$ token is parsed like any other debugger command. Therefore, if you want to create a comment after another command, you must precede the $$ token with a semicolon.
The $$ token will cause the text after it to be ignored until the end of the line or until a semicolon is encountered. A semicolon terminates the comment; text after the semicolon is parsed as a standard command. This differs from * (Comment Line Specifier), which makes the remainder of the line a comment even if a semicolon is present.
For example, the following command will display eax and ebx, but not ecx:
0:000> r eax; $$ some text; r ebx; * more text; r ecx
Text prefixed by the * or $$ tokens is not processed in any way. If you are performing remote debugging, a comment entered in the debugging server will not be visible in the debugging client, nor vice-versa. If you wish to make comment text appear in the Debugger Command window in a way visible to all parties, you should use .echo (Echo Comment).