How to get the difference between files

I've found other links on the stackoverflow communities that were similar but they didn't answer my question exactly. I have 2 files with a different number of lines BUT I have them both sorted. My original files are hundreds of lines long but for troubleshooting purposes, I made file1 have 12 lines and file2 have 5 lines. File2 is a subset of file1. What I want to do is run a command that outputs all the lines that are in file1 but are not in file2. I tried using the Unix commands diff and comm but they both list the full contents of file1, which is not what I want. A quick example of this would be: File1 File2 A B B E C I E N G O I L M N O X So here, we can see everything that's in file2 is in file1. For some reason, diff and comm both showed the full contents of file1. I assume it's because it's doing a line by line comparison and not searching thru the whole file. Is there another Unix command I can run that will output what I am expecting? EDIT: The commands I used to attempt to get what I needed were: a) diff file1 file2 This basically listed everything from file1 with a in front of it. Definitely not what I needed b) comm -23 file1 file2 This showed the whole content of file1 again and not the diff like I was expecting. I also c) comm -3 file1 file2 The help page for comm said this would print lines in file 1 but not in file 2 and vice versa but this also didn't show what I wanted b/c in my example, B appears in both files but on different lines. However, the output thinks it's in one but not the other and therefore prints it out. So the output looked like this: A B B C E E etc. And it wasn't what I was expecting. I was expecting A C G L M X