We had a similar question a couple of weeks back. On that ocasion the suplicant had a multi gigabyte file in a static format that they wanted to search quickly.

In your case, the simplest soution to search and count for single words is to use grep. eg:

This approch is simple, and reasonably fast. If you want more speed you would need to construct an index, and the best way to do that would be to use a database. In the thread referenced above, erix documented how to import the data into a PostgreSQL database. It took about several minutes to import and index the data, but once that was done, searches took around a tenth of a millisecond.

If your data is not structured, then you would have more work to import it into a database, but it can still be done.