You know what, tilly is right. I always get into trouble every time I assume that unpack will do its job faster than a regexp.

Here's a test snippet proving tilly's point and disproving my earlier assertion:

use strict;
use warnings;
use Benchmark;

my @stuff;

while ( my $line = <DATA> ) {
    chomp $line;
    push @stuff, $line;
}

sub do_split {
    my @parsed;
    push( @parsed, 
        split( /\|/, $_ ) 
    ) for @stuff;
    return scalar @parsed;
}

sub do_unpack {
    my @parsed;
    push( @parsed, 
        unpack( 'a5xa5xa5xa5xa5xa5xa5xa5xa5xa5x', $_ ) 
    ) for @stuff;
    return scalar @parsed;
}

my $count = 100000;

timethese ( $count, {
    SPLIT => \&do_split,
    UNPACK => \&do_unpack
    }
);

__DATA__
AAAAA|BBBBB|CCCCC|DDDDD|EEEEE|11111|22222|33333|44444|55555|
FFFFF|GGGGG|HHHHH|IIIII|JJJJJ|11111|22222|33333|44444|55555|
KKKKK|LLLLL|MMMMM|NNNNN|OOOOO|11111|22222|33333|44444|55555|
PPPPP|QQQQQ|RRRRR|SSSSS|TTTTT|11111|22222|33333|44444|55555|
UUUUU|VVVVV|WWWWW|XXXXX|YYYYY|11111|22222|33333|44444|55555|
ZZZZZ|aaaaa|bbbbb|ccccc|ddddd|11111|22222|33333|44444|55555|
AAAAA|BBBBB|CCCCC|DDDDD|EEEEE|11111|22222|33333|44444|55555|
FFFFF|GGGGG|HHHHH|IIIII|JJJJJ|11111|22222|33333|44444|55555|
KKKKK|LLLLL|MMMMM|NNNNN|OOOOO|11111|22222|33333|44444|55555|
PPPPP|QQQQQ|RRRRR|SSSSS|TTTTT|11111|22222|33333|44444|55555|
UUUUU|VVVVV|WWWWW|XXXXX|YYYYY|11111|22222|33333|44444|55555|
ZZZZZ|aaaaa|bbbbb|ccccc|ddddd|11111|22222|33333|44444|55555|
[download]

The output:

Benchmark: timing 100000 iterations of SPLIT, UNPACK...
  SPLIT: 25 wallclock secs (23.92 usr +  0.01 sys = 23.93 CPU)
      @ 4178.16/s (n=100000)
  UNPACK: 26 wallclock secs (25.62 usr +  0.01 sys = 25.63 CPU)
      @ 3902.13/s (n=100000)
[download]