如何使用sed for windows（来自cygwin）替换utf16文件

I am using sed from cygwin on Windows to do some substitutions in text files. Everything works fine for normal (ANSI) files, but it doesn't do anything for utf-16 files (no substitutions are made). Do you know how I can make it work for both types of files at the same time? I am using sed from cygwin on Windows to do som