Also, your NUM_CHLDS is either a misnomer, or your usage creates one more child than you intended.

You could make your loop more perl-ish by re-writing it as:

for(1 .. $NUM_CHLDS) {
  push @pids, my $pair  = { child_fh  => undef,
                            parent_fh => undef,
                            pid       => undef
                          };
  socketpair($pair->{child_fh},$pair->{parent_fh},
    AF_UNIX,SOCK_STREAM,PF_UNSPEC) or die "socketpair at $_: $!\n";
.....

#For Reading the @pids array, instead of for(0 .. $NUM_CHLDS) , use:
foreach my $pair(@pids)
{
  close $pair->{parent_fh};
  syswrite($pair->{child_fh},$line,LINE_LEN);
}
[download]