You can also use grep, using e.g. the qx// feature, and read that output as the way of identifying those files that you might need to explore further.

You can do a lot of useful things in a Unix-shell environment by “piping” together these very useful commands:

• grep
• xargs
• awk
• perl (of course)

I put perl in that list, not for humor’s sake, but to point out that Perl doesn’t have to be front-and-center in whatever approach you take.   You can get a lot of very useful work done very fast by “stitching together” existing tools, sometimes eliminating the need to write a single program to do it.