#!/usr/bin/perl -w
use strict;

my @word = qw(xxx yyy zzz);
open(PF,"|grep xxx") or die "failed \n";
foreach(@word) {
  print "here \n";
  print PF $_;
}
print "going to close filehandle\n";
close(PF) or die "failed\n";
print "here 2\n";