What makes code Perlish?

There is a lot of discussion in lots of places about "perlish" code. What perlish code is. What it isn't. But, not a lot about how you can tell the difference.

The first metric to look for is conciseness. How many lines of code does it take to express a concept? For example, swapping a two variables. In most languages, you have to use an explicit temp variable, such as in the following C code:

temp = i;

i = j;

j = temp;

That's three lines to express a single concept. Most imperative languages require the same thing. Perl (and similar languages like Python and Ruby) does it in one.

( $i, $j ) = ( $j, $i );

Two lines doesn't sound like much. But, think about it as a 3-to-1 reduction. That means 300 lines is now 100. Ohhhh.