Hello BillKSmith,

I had no idea, great module thanks for pointing it also to us.

Just to include a complete answer for future reference I will also add sample of code.

#!/usr/bin/perl
use strict;
use warnings;
use Capture::Tiny 'capture';

my $cmd = 'setop --intersect ' . join ' ', @ARGV;

my ($stdout, $stderr, $exitCode) = capture {
    system( $cmd );
};

print $stdout if $exitCode == 0;
print 'Error: ' . $stderr unless $exitCode == 0;

__END__

$ perl test.pl File1.txt File2.txt File3.txt
ID121    ABC14
ID122    EFG87
ID157    TSR11
[download]

BR / Thanos