use strict;

my %hash;
my @dirs;
@dirs = qw(ONE TWO THREE FOUR);

for my $loop(@dirs)
   {
   pipe (FROM_CHILD_$loop, TO_PARENT_$loop) or die "Oops Pipe: $!\n";
   select((select(TO_PARENT_$loop), $|++ )[0]); # set autoflush
   $|++;
   my $test = rand 5;    # simulate processing
   print TO_PARENT_$loop "$test $loop\n";
   }

for my $loop(@dirs)
   {
   chomp( my $in = <FROM_CHILD_$loop> );
   (my $value, my $key) = split(/\ /, $in);
   $hash{$key} = $value;
   }

close FROM_CHILD_$loop; 
close TO_PARENT_$loop;

for my $loop(keys %hash)
   {
   print "keys $loop => $hash{$loop}\n";
   }