Searching for a List of Words in a Large File

I’ve used this during our repo process to search through the Netscaler config backup and clean up any server names that are no longer in use.

find a very long list of words in big files:

A.txt - source file

B.txt - list of words to search in A.txt

prep the source file by removing the last \n of A.txt:

$ tr '\n' '|' < A.txt > A.txt_regex

then run egrep:

$ egrep -f A.txt_regex B.txt > Results.txt