#!/usr/local/bin/perl
use strict;
use warnings;
use Bio::SeqIO;

my $file = "Test.fasta";
my $in = Bio::SeqIO->new(
        -file => "<$file",
        -format => 'fasta',
        -flush=>0
        );

while (my $seq=$in->next_seq){
        my $desc = $seq->desc;
        print $desc, "\n" ;
        }