Using :encoding(UTF-16) on a file not encoded using UTF-16 will likely die as a result of not finding \xFE\xFF or \xFF\xFE at the start of the file.

Using :encoding(UTF-16le) on a file not encoded using UTF-16le will result in garbage and/or die.

You must know the encoding of the file to be able to read it.

I think File::BOM will help you. It imposes an limitation (the presence of a BOM for non-default encodings), but that doesn't sound like a problem for you.