use strict;
use warnings;
my @labels = ('fee', 'fi', 'fo', 'fum');
open(my $fh, '<', "folks.txt") || die "can't open folks: $!";
my @list;
while (<$fh>) {
  chomp;
  push @list, [split /,/];
}

for my $i (0 .. 3) {
  for my $element (@list) {
    print "$labels[$i],$element->[0],$element->[$i+1]\n";
  }
}