while(<FH>){
   if($_ =~ C B A R){
      do something
   }
   if($_ =~ Q U A D){
      do something
   }
   if($_ =~ C R O D){
      do something
   }
   if($_ =~ C B E A M){
      do something
   }
   if($_ =~ C E L A S 1){
      do something
   }
  ... 
}


##</code><code>##

 
while(<FH>){
   if($_ =~ C B A R){ # selected element
      do something
   }
   if($_ =~ Q U A D){ # selected element
      do something
   }

}