use strict;
use warnings;
require 5.008_008;
use Carp;
use English qw( -no_match_vars );
[...]
open my $fh, '-|', "$command"
  or carp "Error while executing command:$ERRNO\n";
my @command_output = <$fh>;
close $fh 
  or carp "ERROR: Couldn't close filehandle: $ERRNO\n";