How could I compare two files and remove similar rows in them (bash script)

Question

I have two files of data with similar number of columns. I\'d like to save file2 in another file (file3) while I exclude the rows which are existed already in the file1.

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Answer 1

grep -v -f is problematic because it searches file2 for each line in file1. With large files it will take a very long time. Try this instead:

comm -13 <(cat file1 | tr '\t' ' ' | sort) <(sort file2)