## UNTESTED
use strict;

my %hash;
open(FH,'<','oldfile') or die "$!\n";
foreach (<FH>) {
  chomp;
  my ($key,$data) = split(/\|/,$_,2);
  $hash{$key} = $data;
}
close FH;

open(NEW,'<','newfile') or die "$_\n";
open(OUT,'>','outfile') or die "$_\n";

foreach (<NEW>) {
  chomp;
  my ($key) = split(/\|/,$_,2);
  if ( exists $hash{$key} ) {
    print OUT "$hash{$key}\n";
  }
}