# method 1
my $value = join '|', @final_array;
while (<DOC>) {
  s/$value/pagingRAC/g;
  print
}


# method 2
my $doc = do { local $/; <DOC> };
my $value = join '|', @final_array;
$doc =~ s/$value/pagingRAC/gm;
print $doc;


# method 3
my $value = join '|', @final_array;
print for map { s/$value/pagingRAC/g; $_ } <DOC>;