10 PRINT "<29>This should be dim.<30>EThis should be reversed.<28>This is bold."

##</code><code>##

10 PRINT @(-38);"This should be dim.";@(-37);"This should be reversed.";@(-40);"This is bold."

##</code><code>##

while ($line=~/(<\d+>)/g) {
 next if ($1 eq '<30>');
 $line=~s/$1/$fix{$1}/;
}