Check out the code below (inspired by a comment from dws in a recent chatterbox discussion) 
use Benchmark;

sub sub1    {   my $fh;
                open $fh, 'vsfull.csv';
                binmode $fh;

                my @lines;

                my $block; my $left = '';
                while( read $fh, $block, 8192 ){

                    $block = $left . $block;
                
                    my $i = index $block, "\n";
                    while($i > 0){
                    
                        push @lines, substr($block,0,$i);
                        substr($block,0,$i+1,'');
                        $i = index $block, "\n";

                    }

                    $left = $block;

                }
                
            }

sub sub2    {   my $fh;
                my @lines;
                open $fh, 'vsfull.csv';

                while(<$fh>){ push @lines, $_ };

            }

timethese( 100, { readbig  => \&sub1, whilelp  => \&sub2 });

[download]
The results? 
Benchmark: timing 100 iterations of readbig, whilelp...
   readbig: 25 wallclock secs (25.21 usr +  0.00 sys = 25.21 CPU) @  3
+.97/s (n=100)
   whilelp: 157 wallclock secs (156.71 usr +  0.00 sys = 156.71 CPU) @
+  0.64/s (n=100)

[download]
Now admittedly, my code is probably clunky and whatnot, but I would assume that this would be the model one would follow for splitting a file into multiple lines. My question has two parts: why would one use <> when it's so slow relative to read, and why hasn't <> been implemented in such a fashion that it takes advantage of read's quickness? Cluka

In reply to Why use <$fh> at all? by cluka

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