see: a marker such as FFFD (REPLACEMENT CHARACTER) in http://unicode.org/faq/utf_bom.html

and see native2ascii --help

 Specifies the name of the character encoding to be used by the conversion procedure. If this option is not present, then the default character encoding (as determined by the java.nio.charset.Charset.defaultCharset method) is used. The encoding_name string must be the name of a character encoding that is supported by the JRE. See Supported Encodings at http://docs.oracle.com/javase/8/docs/technotes/guides/intl/encoding.doc.html 

see: a marker such as FFFD (REPLACEMENT CHARACTER) in http://unicode.org/faq/utf_bom.html

and see native2ascii --help

 -encoding encoding_name Specifies the name of the character encoding to be used by the conversion procedure. If this option is not present, then the default character encoding (as determined by the java.nio.charset.Charset.defaultCharset method) is used. The encoding_name string must be the name of a character encoding that is supported by the JRE. See Supported Encodings at http://docs.oracle.com/javase/8/docs/technotes/guides/intl/encoding.doc.html 

a case

$ file yourfile.properties yourfile.properties : ISO-8859 text, with very long lines $ native2ascii -encoding ISO-8859-1 yourfile.properties yourfile.properties