filter a file with other file in bash

Question

i Have a file with numbers, for example:

$cat file
31038467
32048169
33058564
34088662
35093964
31018168
31138061
31208369
31538163
31798862

and other for example with

$cat file2

31208369
33058564
34088662
31538163
31038467

Then i need other file with lines that are in the first file but not in the second

cat $output
35093964
31018168
31138061
31798862
32048169

My real file has 12'000.0000 of lines.

Then how can i do it?

Answer 1

Is

grep -f file2 -v -F -x file1

sufficient?

NOTE1: Please specify in question, if the actual question is that, you need it to be time/memory optimized.

NOTE2: Get rid of any blank lines in file2.