I’m confused as to what you are searching for.
Especially since you are using multiple instances of “*”
— Which with regex are rarely necessary, and frequently will mangle your search results.
[[:alnum:];.] —> means match *ANYTHING*
You haven’t escaped the period. and it will match any char.
Possibly you meant:
[[:alnum:];.]
But then, this: ([[:alnum:];.])*
Means match any alphanumeric plus semi-colon plus a dot any number of times, or not at all. Meaning it will also match empty lines – that only have a carriage return.
Possibly, what you meant as your regex:
: ([[:alnum:];.])+n