use strict;
my $str = '';
my $regex = qr/\((?!([^\(\)\[\]]*(\b)(ARR|ARRANGEMENT|ARRANGEMENTS|ARRANGED|CHOPPED|DUB|EDIT|FT|FEAT|FEATURING|INSTRUMENTAL|MASH UP|MASHUP|MASH-UP|MIX|REMIX|REPRISE|SCREWED|TITLE|VERSION)(\b)[^\(\)\[\]]*)).*?\)/p;
my $subst = '';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html