#!perl -p

s/($regex)/$1 ($acronyms{$1})/g;

BEGIN {
  %acronyms = (
    'HTML'    => "Hypertext Markup Language",
    'ICBM'    => "Intercontinental Ballistic Missile",
    'EEPROM'  => "Electronically-erasable programmable read only memory",
    'SCUBA'   => "Self Contained Underwater Breathing Aparatus",
    'FAQ'     => "Frequently Asked Questions",
    'LCARS'   => "Library Computer And Retrieval System",
    'NASA'    => "National Aeronautical and Space Administration"
  );
  
  $regex = join '|', map quotemeta, 
		sort { length($b) <=> length($a) } keys %acronyms;
}