use strict;
use warnings;
use Text::CSV_XS qw( csv );

my @result;
foreach my $f (sort glob "*.txt") { # Use File::Find for recursive actions
    csv (in => $f, headers => "auto", sep => "\t", on_in => sub {
        push @result => $_{fooble};
        });
    }
open my $fh, ">", "results.txt" or die $!;
say $fh $_ for grep { length } @result;
close $fh;