Your advice looks a bit like hermetism to me - for the moment ;-)

So i need just a moment to think about/try it.

But BTW, here is what i figured out in a hurry using IPC::Run as advised by kschwab:

#!/usr/bin/env perl                                                   
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use IPC::Run qw( start finish );
use strict;
use warnings;

my @cat = qw( cat foo );

my @wc = qw( wc -l);

my $h = start \@cat, '|', \@wc, '2>', '/dev/null';

$h->finish;

print $h->full_result(0) . qq(\n);

print $h->full_result(1) . qq(\n);

__END__

karls-mac-mini:Desktop karl$ ./ipc.pl                                 
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       0                                                              
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1                                                                     
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0
[download]

Looks good/like expected. Best regards, Karl