Comm for learning linux commands based on scenarios

I learned linux commands in combination with the scenario. comm asked me a question today. the model is such A set A-set B how to do it in linux. set A is placed in data1, and set B is placed in data2. what she started with was that the common-2-3data1data2 looked like it was normal...
I learned linux commands in combination with the scenario. comm asked me a question today. the model is such A set A-set B how to do it in linux. set A is placed in data1, and set B is placed in data2. in her first practice, the common-2-3 data1 data2 seems to be normal. -2 suppress column 2 (lines unique to FILE2)-3 suppress column 3 (lines that appear in both files)-2: indicates that the second column is not output (only in FILE2) -3: The third column is not output (both FILE1 and FILE2 are displayed, that is, the intersection of set A and set B ). after man comm, she found a simple error. www.2cto.com comm-compare two sorted files line by linecomm requires files to be ordered. we recommend that you use sort to get the desired result. here we provide A method to remove A-set B except comm. cat FILE1 FILE2 FILE2 | sort | uniq-u the principle is simple: when FILE2 appears twice, the elements in FILE2 must be repeated, if the file element in FILE1 is the same as that in FILE2, it will be removed by uniq-u.