$rc = 1;
while (defined($nextfile = <$dirName/*cm*.4gl>))
{
  if ($rc) {
    $rc = system("grep $field $nextfile 1> /dev/null");
    if (!$rc) {
      print FOUND "$field $nextfile\n";
    }
  }
}

##</code><code>##

for my $nextfile (glob File::Spec->catfile($dirName, '*cm*.4gl')) {
  $rc = system("grep $field $nextfile 1> /dev/null");
  if (!$rc) {
    print FOUND "$field $nextfile\n";
    last;
  }
}