Negative lookarounds are usually what you're after:
Negative Lookbehind
- [code](?<!status )code[/code] matches code not preceded by status
- [code](?<!status )(?<!post)code[/code] matches code not preceded by status or by post
Negative Lookahead
- [code]code(?!smith)[/code] matches code not followed by smith
- [code]code(?!smith)(?!d)[/code] matches code not followed by smith or by d
Negated Character Classes
But to not-match just a single character you can do it with character a class:
- [code]code[^d][/code] matches code but not coded
- [code]code=[^0-9][/code] matches code=X where X is not a digit