sub ret_read_fh {
  my $filename = shift;
  my $fh = do {local *FH};
  unless(open($fh, "< $filename")) {
    log_error("open '$filename': $!");
    return;
  }
  unless(flock($fh, 1)) {
    log_error("flock '$filename': $!");
    return;
  }
  return $fh;
}

sub display_values_from_file {
  my $fh = ret_read_fh(shift);
  if ($fh) {
    while(<$fh>) {
      print process_line_from_file($_);
    }
  }
  else {
    print "Error opening file.  Please try again later!";
  }
}