When offering instruction to someone who is obviously new to perl it would be best to take the opportunity to teach them. Whether that is done by providing hints, or providing a solid solution is of course up to the author.

The solution you provided is close to what he was asking for, but it would have been better to use strict and warnings to encourage good habits, and it would be good to offer links to the syntax/idioms that might be unfamiliar to the original poster. For example, he might not be familiar with the ternary operator or the autoflush variable