foreach my $keys (keys %hash) { foreach my $z (keys %hash) { if ($hash{lc $keys} = $hash{$z}) { $hash{$z} = $hash{$z} + $hash{$keys}; delete $hash{$keys}; } } } foreach my $value(sort {$hash{$b} <=> $hash{$a}} keys %hash) #frequency list { print "$value\t\t$hash{$value}\n"; }