my @lines = [];
#
# THE MAIN PROGRAM READS THE FILE LINE-BY-LINE, CLASSIFYING THEM 
# USING REGULAR EXPRESSIONS
# 
while(<>) {
  if (/^\<SUBBEGIN) {   # STARTING LINE 
    @lines = [];
  }
  elsif(/^<SUBEND/) {  # ENDING LINE
    look_for_patterns();
  }
  # INSERT "elsif" CASES HERE TO FILTER OUT BLANK LINES 
  # OR OTHER UNWANTED "JUNK," IF APPLICABLE ...
  #
  else {   # "EVERYTHING ELSE" 
    push @lines, $_
  }
}
look_for_patterns();   # IF APPROPRIATE – MAY NOT BE, FOR THIS CASE

# THIS SUBROUTINE EXAMINES EACH ACCUMULATED GROUP OF LINES
# LOOKING TO SEE IF BOTH DESIRED PATTERNS ARE INSIDE.
sub look_for_patterns {
   my $CFU_seen = 0;
   my $CFB_seen = 0;
   foreach (@lines) {
     if (/CFU-TS10-ACT/) {
       $CFU_seen = 1;
     }
     elsif (/CFB-TS10-ACT/) {
        $CFB_seen = 1;
     }
   }
  if ($CFU_seen && $CFB_seen) print "Yay!\n";
}