#!/usr/bin/perl

use strict;
use warnings;
use Benchmark qw/cmpthese/;

my $count = 100;   
cmpthese(
    $count,
    {   'line' => sub {
            my $f1;
            open( $f1, "< file" );
            while ( my $l = <$f1> ) {
                push( my @ll, $l );
            }
            close($f1);
        },
        'all' => sub {
            my $f1;
            open( $f1, "< file" );
            my @ll = <$f1>;
            close($f1);
            }
    }
);