How to search for multiple strings in a file

Question

I want to search for the occurrence of string1 OR string2 OR string3, etc. in a file, and print only those lines (to stdout or a file, either one). How can I easily do this in bash?

Answer 1

you can also use awk

awk '/string1|string2|string3/' file

With awk, you can also easily use AND logic if needed.

awk '/string1/ && /string2/ && /string3/' file

Answer 2

grep "string1\|string2\|string3" file_to_search_in