use strict;
use warnings;

my @names   = split(' ', <DATA>);
my @lenghts = split(' ', <DATA>);

my %sizes;
@sizes{@names} = map { length } @lenghts;

sub strip_space {
    my ($str) = @_;
    $str =~ s/^\s+//;
    unpack 'A*', $str;
}

my %data;
while (defined(my $line = <DATA>)) {
    my $pos = 0;
    foreach my $name (@names) {
        push @{$data{$name}},
          strip_space(substr($line, $pos, $sizes{$name}));
        $pos += $sizes{$name} + 1;
    }
}

use Data::Dumper;
print Dumper \%data;

__END__
Mod  Sub-Module                  Model              Serial
---- --------------------------- ------------------ -----------
  1  Distributed Forwarding Card WS-F6700-DFC3CXL   SAL1434RLPY
  3  7600 ES+ DFC XL             7600-ES+3CXL       JAE14520N29
  3  7600 ES+T 20x1GE SFP        76-ES+T-20GQ       JAE145301XM
  5  Policy Feature Card 3       7600-PFC3CXL       JAE14330E6J
  5  C7600 MSFC4 Daughterboard   7600-MSFC4         JAE14320QBE
  6  Policy Feature Card 3       7600-PFC3CXL       JAE14330EAO
  6  C7600 MSFC4 Daughterboard   7600-MSFC4         JAE14320QA8
  7  Distributed Forwarding Card WS-F6700-DFC3CXL   SAL1433QHBR
  8  Distributed Forwarding Card WS-F6700-DFC3CXL   SAL1433QXF9
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