I have a file with many strings. For simplicity, assume it is newline-delimited, and that each string is made up of only contain alphanumeric ASCII characters and underscore.
Now, I want to search a file / multiple files for occurrences of any of these strings. If there are not very many of them, I suppose I could just concatenate them with
| and use a single grep. But - what if there are thousands, or tens of thousands, of them?