By choosing a different regex delimiter and using a ? (0 or 1) quantifier you can make this line

next if ( "$dir_name/$file" =~ /\/\.$/ or "$dir_name/$file" =~ /\/\.\.
+$/ );
[download]

simpler and more readable

next if "$dir_name/$file" =~ m{/\.\.?$};
[download]

Cheers,

JohnGG