I am not sure why, but your link did not work for me - I found www.perlfaq.com helpful, kumar's exact question can be found here.

I also could not find a solution in the perldoc.com FAQ specifically addressing this question (though I am sure it is there somewhere).

I however did find kumar's question (and answer) here on PM in our own Q/A section here.

Cheers - L~R

Update: Links point directly to solution