Most efficient way of taking a subset of lines

Question

I have two files. One huge one (200.000+ lines) called 'db' and one big one (15.000+ lines) called 'indices'.

What is the quickest way of filtering out the lines in 'db' containing any index (anywhere on the line) from 'indices'

The solution I could think of is

for index in $(cat indices); do
  grep $index db >> selection
done;

but this is taking a long time.

Is there a faster approach in bash, linux?

Answer 1

fgrep -f indices db 

should be faster.