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 $retval = 1;
  if ($retval == 1) {
    print "**Error occurred .........etc.\n";
  }
  else {
    print "**Successfully put file(${source_directory}/${file_name_to_xfer}) to host($host).\n";
  }
  return $retval;
} # End ftp_put_file()