比较两个文件和歌曲列表的最简单方法

I have two lists of song titles, each in a plain text file, which are the filenames of licensed lyric files - I want to check if the shorter list titles (needle) are in the longer list (haystack). The script/app should return the list of titles in the needle that aren't in the haystack.I have two lists of song titles, each in a plai