use strict;
use warnings;
use Data::Dumper;
my @headers = split /\s/, <DATA>;
print Dumper \@headers;
my $length = @headers;
my @all;
while (my $line = <DATA>){
    my $row = [split /\s/, $line, $length];
    push @all, $row;
}
print Dumper \@all;
__DATA__
col1 col2 col3 col4
a b c d
1 2 3 4