The utf8 pragma allows you to write perl source code encoded in utf-8. that means utf-8 strings, variable names, and regular expressions. utf8::all goes further, and makes @argv encoded in utf-8, and filehandles are opened with utf-8 encoding turned on by default (including stdin, stdout, stderr). if you don't want utf-8 for a particular filehandle, you'll have to set binmode $filehandle.