#!/usr/bin/perl -wT
use strict;
use IPC::Open3;

$ENV{PATH} = '/sbin';

my ($wtr, $rdr, $err, $ret);
my $pid = open3($wtr, $rdr, $err, 'ifconfig', '-abc');
close $wtr;
waitpid $pid, 0;
$ret = $? / 256;

if ($ret == 0) {
   while (my $line = <$rdr>) {
      print $line; # oder deine Verarbeitung
   }
} else {
   local $/;
   my $errors = $err ? <$err> : <$rdr>;
   print STDERR "Unable to execute ifconfig: ($ret)\n";
   print STDERR "$errors" if $errors;
}

close $rdr;
close $err if $err;

exit $ret;