my @FILES = grep { -f } readdir (TEMP);
foreach my $file (@FILES){
  open (F, $file) or warn "Couldn't open $file: $!" and next;
  my @matches = grep {  /$str/ }  <F>;
  close (F);
  next unless scalar @matches > 0;
  print join("\n", @matches); 
}

##</code><code>##

print $matches[0], "\n";