Just out of interest, I reached for my Camel Book (1st Edition). On page 78, the second paragraph is a very close copy of what ++haukex has quoted from the current documentation.

In the INTRODUCTION section of perlhist, you'll see:

"Perl 4 introduced the first Camel book. Really. We mostly just switched version numbers so the book could refer to 4.000."

So, that feature has been around since Perl 3; and, it would appear, hasn't substantially changed. It's possible it worked exactly the same in earlier versions; however, I'm not in a position to comment on that.