It's actually the shell that is so smart. Pretty much any language (at least, any with some form of ARGV-like construct) is going to parse it correctly. You see, the shell doesn't pass your program the character string from the command line, rather the shell passes your program an array of parameter strings.

This is why if you look at system(...) or exec(...), you see that they take a list as their argument (or, again, whatever parallel construct in any other language). You also see that if you only pass one item in that list, and it contains characters which the shell will know how to handle, that perl actually invokes the shell to handle converting that string into the @ARGV of the sub-process.