# disclaimer - assume use strict and warnings are both in effect, and 
# variables are lexically named elsewhere..  this is a toss off bit o' code

while (my $line = <FH>) {
  
  $test =~ join ( split ( /(?:[^A-Z])/, $line ) );
  
# the previous line will excise any non uppercase, non letters from $line
# now, we compare $line to our $foo
  
  while ($test =~ /$foo/g ) {
    $line =~ s/$1/(stuff1 . $1 . $stuff2)/e
    }
  
  }