character_tests.pl: Use of uninitialized value in split at character_tests.pl line 132 character_tests.pl: Use of uninitialized value $first_book in pattern match (m//) at character_tests.pl line 134 character_tests.pl: Use of uninitialized value $first_book in pattern match (m//) at character_tests.pl line 134 character_tests.pl: Use of uninitialized value $first_book in substitution (s///) at character_tests.pl line 135 character_tests.pl: Use of uninitialized value $first_book in array element at character_tests.pl line 136