use strict;
use warnings;

my    $header  = <DATA>;
chomp $header;
      $header  =~ s/ ^ \s+ //x;
my    @columns = split /\s+/, $header;
my    $columns = scalar @columns;
my    @lines   = <DATA>;
my    $data    = pop @lines;
chomp $data;
my    @data    = split /\s+/, $data;

print "\t", join("\t", @columns), "\n";

for my $line (@lines)
{
    chomp $line;
    print $line;

    for my $i (1 .. $columns)
    {
        print("\t", shift @data) if @data;
    }

    print "\n";
}

__DATA__
    a       b    c    d    e    f    g    h
aa
bb
cc
dd
aa
bb
cc
dd
aa
bb
cc
dd
1    2    3    4    5    6    7    8    9    10    11    12    13    14    15    16

##</code><code>##

17:37 >perl 2021_SoPW.pl
        a       b       c       d       e       f       g       h
aa      1       2       3       4       5       6       7       8
bb      9       10      11      12      13      14      15      16
cc
dd
aa
bb
cc
dd
aa
bb
cc
dd

17:37 >