my @ids =<IDLIST>;

my $dir = $opts{d};
chdir($dir) or die "$!";
opendir(DIR, ".") or die "Can't open $dir: $!";
my @files = grep {/fa$/}  readdir DIR;
close DIR;
foreach my $id (@ids) {
   foreach my $fasta (@files){
		local @ARGV = @files;
		print grep (/$id/,<>), "\n";
   }
}