sub build_regexp {
  my $expr = join '|', map { "(?:To|is)\:\S+\@$_" } @_;
  eval { $expr = qr/$expr/i  };
  die "aaa!! $@ !!!" if $@;
  $expr;
}


##</code><code>##

my $writeFh = new FileHandle ">> myout.log";
my $is_subset = build_regexp(@allSubSets);

while (<fh>) {
    next unless /$is_subset/;
    print $writeFh <$fh>;   
}