my %hash = (
            abca => {comment => 'a_b__ca', para1 => 1, para2 => 2},
            abcb => {comment => 'a_b__cb', para1 => 7, para2 => 2},
            abcc => {comment => 'a_b__cc', para1 => 4, para2 => 2},
            abcd => {comment => 'a_b__cd', para1 => 9, para2 => 2},
        );