sub ftp_put_file {
  # If rename_file = "Y" transfer file with '.xferring' as extension.
  if ( $rename_file eq "Y" ) {
    $file_name_to_xfer = "$file_name.xferring";
  }
  else {
    $file_name_to_xfer = $file_name;
  }
  $ftp->put( "$source_directory/$file_name", $file_name_to_xfer ) or die "Failed to transfer $source_directory/$file_name: ".$ftp->message();
  print "**Successfully put file($source_directory/$file_name_to_xfer) to host($host).\n";
  return 1;
} # End ftp_put_file()