Filename is either
Stuff.1999.600d.other.txt
Or
Stuff.1999.other.txt.
If the former, I want the new filename to be:
Stuff (1999) [600d] other.txt
If the latter I want:
Stuff (1999) other.txt,
But instead I'm getting:
Stuff (1999) [] other.txt
Because the second numeric string is an empty match.
How can I optionally insert the brackets based on successfully matching the second numeric string?
Thanks.