use warnings;
use strict;
my $usage = "perl select_bracker.pl [bracker gtf] [output id list]\n";
my $gfin = shift or die $usage;
my $output = shift or die $usage;
open(IN, '<', $gfin);
open(OUT, '>>', $output);
while (my $record = <IN>){
	$record =~ s/\R//g;
    if ($record =~ /^.*transcript_id "([^"]*).*class_code "([^"]*)/){
		my $trans = $1;
		my $class = $2;
		if($class eq 's' | $class eq 'x' | $class eq 'u'){
			print OUT "$trans\n";
		}
	}
}
close IN;
close OUT;