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.

<

Answer 1

Try:

grep -Fxvf file1 file2

Switch meanings available from the grep man page.

Answer 2

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)

Answer 3

You can convert tabs to spaces on the fly:

grep -vif <(tr '\t' ' ' < file1) file2 > file3

This is process substitution.