# Okapi Framework - Utilities ## Byte-Order-Mark Conversion
Utilities | Okapi Framework

If you are using an Okapi Tool after the M9 release, you should be using the wiki online help:
http://www.opentag.com/okapi/wiki/index.php?title=Rainbow

This utility allows you to add or remove the Byte-Order-Mark (BOM) to or from UTF-8 and UTF-16 files.

The Byte-Order-Mark is a special Unicode mark that is used to indicate if a file is in little-endian (U+FEFF) or big-endian (U+FFFE) mode. For more information on the BOM see http://www.unicode.org/faq/utf_bom.html.

This utility does not use filters.

## Input Parameters

- The list of the input documents to modify (Input list 1).
- The default input encoding (when Adding BOM).
- The names and locations of the output documents.

## Configuration

### Options Tab

#### Actions on the Byte-Order-Mark

Remove the Byte-Order-Mark if it is present -- Select this option to remove the BOM from the input files if one is detected. By default only the BOM of UTF-8 files are removed.

Remove also UTF-16 BOMs -- Select this option to also remove the BOM from UTF-16 files if one is detected. This is not something that is recommended: UTF-16 files must have a BOM.

Add the Byte-Order-Mark if it is not already present -- Select this option to add a BOM in the input files if one is not detected. Note that the input files must already be in UTF-8 or UTF-16.

When using this feature, you also must specify the encoding of each file, so the utility can add the proper type of BOM.