Hello geertvc, and welcome to the Monastery!

The glob function expects an expression which evaluates to a string, so use either unlink glob "$_/*.*"; or unlink glob $_ . '/*.*';. (The latter form uses . as the concatenation operator.)

BTW, “has issues” isn’t very informative! In future, please detail the warning or error message(s) you are getting.

Hope that helps,

Update: Added forward slash to the concatenation example. Thanks, AnomalousMonk!