@FILE2 = map { local $_=$_; s/(<Bz8>)([^ ]*)/$1$2<\$>/; $_ } @FILE;

##</code><code>##

s/(<Bz8>)([^ ]*)/$1$2<\$>/ foreach (@FILE);

##</code><code>##

foreach (@FILE) {
   s/(<Bz8>)([^ ]*)/$1$2<\$>/;
}