Take a look at Count number of lines in a text file.

Update: my 2 cents...

use strict;
use warnings;
use IO::All;

my $file = shift || die $!;
my $io = io $file; 

print qq(I think it's more than one!\n) if $io->[1];
[download]

Note: "IO::All file used as an array reference becomes tied using Tie::File".

Regards, Karl