Thanks for taking time to take look at my code. I think you misunderstand my issues. The issues is that I have two files and each files has the multiple sections, and each section contents the description of it. The problem I am want to do is to compare two files and only print out the sections and subsection within that are not in file1 and save to the third file. Your edited code is comparing all the lines but I want to compare the sections and ignore the lines within the section. For example, file2: (Section, eighteen, 3, 4, YELLOW HAIR 3, HIGH, 'this is a cattt 1) has 7 strings) and if the line (7 strings) does match with the line in file 1 then I want to print out the no match information ( ex: Section, eighteen 3, 4, YELLOW HAIR 3, HIGH, 'this is a cattt 1, cccccccccccccc kkkkkkkkkkkkkk... So far, my code print out just (Section, eighteen 3, 4, YELLOW HAIR 3, HIGH, 'this is a cattt 1, ) it does not print out the subsections that belongs to the section, like cccccccccccccc.... . Please help me figure out what is the issues with my code. Thanks so much in advance.