#!/usr/bin/perl
      
        my $file='myimageऄwithधDevanagariमcharsफ.png';
        my $filenew=$file=~ s/(.)(?{ if (ord $1 >127 ){'x'} else {$1} })/$^R/gr;
     
        print "before: ",$file,"\n";
        print "after: ",$filenew,"\n";