#!usr\bin\perl -w
#!/usr/bin/perl
use warnings;
use strict;

open my $HUBFILE, '<', '1048_undefined.tsv' or die $!;
my @hubs;
while (my $line = <$HUBFILE>) {
    push @hubs, $1 if $line =~ /\d+ \t (\w+) \t/x;
}
close $HUBFILE;

open my $OUT, '>', 'hubs.txt' or die $!;
for my $hub (@hubs) {
    print {$OUT} "$hub\n";
}
close $OUT;