Get lines of file1 which are not in file2

Question

I have two long, but sorted files. How to get all lines of first file which are not in second file ?

file1

0000_aaa_b
0001_bccc_b
0002_bcc &         


        

Answer 1

Just run a diff on them:

diff -c file1 file2

The -c (for "context") flag will only display the lines that are different, with two lines surrounding each line.