I don't really have much knowledge to learn if I want to go to the library to study and be competent in library work, but there are probably these things, such as cataloging, interviewing, novelty retrieval (only a few schools are qualified for novelty retrieval), and the collation and digitization of ancient books, but there are no ancient books in general small libraries, which is a little close to archival science and philology, and now many libraries are recruiting subject librarians with different knowledge backgrounds.
But now the construction of digital library is very hot, and computer-related knowledge is very important to the library. Many schools attach importance to this when recruiting. For example, Southwest University named a doctor majoring in computer in this year's recruitment, and Nanjing University also focuses on computers in the training of library science and information science.
So, you like libraries very much. If you really want to work there, study it, which is more systematic and comprehensive. This is the best choice for undergraduate students.