I guess that I probably was not clear enough to explain what I meant. I know what the find command is doing and I know that it has very little (if anything) to do with grep. My point was something else.
I just meant to give another completely different example to show that it does not make too much sense to compare the programming efficiency (in terms, for example, of the quantity of code needed for a specific task) of a shell or built-in Unix command and the coding of the same actions in a Perl program. Because to make the comparison fair, you would need to know the quantity of code that is used behind the scene (e.g. the source code of the find command) when you run a find command. I used a very simple grep example just to make the case more obvious.