#!/usr/bin/perl

use strict;
use warnings;
use FileHandle;
use Data::Dumper qw/Dumper/;

my $file = 'test.txt';

my $fh = FileHandle->new();

my @ids = ();

if( $fh->open($file, "<") ) {
	while( my $line = $fh->getline() ) {
		my ($id) = $line =~ m/^((?:[^\t]+\t){3}[^\t]+)/;
		push @ids, $id;
	}
	$fh->close();
}else{
	die("Error reading file $file: $!");
}

print Dumper \@ids;