Perl

Convert a File's Character Encoding from UTF-8 to UFT-8-BOM

See more HTML-to-XML/Text Examples

To add a utf-8 BOM to a file is just a matter of prepending these 3 bytes to the file: 0xEF 0xBB 0xBF.

This may be difficult in some programming languages, or it may be trivial in either. Therefore, the Chilkat solution you see here might be helpful, or in a language such as C++, the Chilkat solution isn't really necessary because it's easy to do yourself.

Perl

use chilkat();

$success = 0;

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$charset = chilkat::CkCharset->new();

$charset->put_FromCharset("utf-8");
$charset->put_ToCharset("bom-utf-8");

$success = $charset->ConvertFile("qa_data/txt/helloWorld.txt","qa_output/helloWorldBom.txt");
if ($success != 1) {
    print $charset->lastErrorText() . "\r\n";
    exit;
}

print "Success." . "\r\n";