[[Perl]]

       @ls = `ls *.txt`;
       chomp @ls;
       foreach$file(@ls){
               $file_utf8 = $file;
               $file_utf8 =~ s/\.(.*)?$//;
               $file_utf8.= ".utf8";
               system("nkf -w $file > tmp");
               system("mv tmp $file_utf8");
               print "nkf -w $file > tmp\n";
       }