use strict;
use IPC::Open3;  
                                                                                                                                                            
my $debug = open3(\*WRITE, \*READ, \*ERROR, "perl -Mre=debug -e 'qr/.../'");

#old incorrect stuff :)
#while (<READ>||<ERROR>) {
#    my (@read, @error) = (<READ>, <ERROR>);
#    print "READ: @read\n";
#    print "ERROR: @error\n";
#}

print <ERROR>;
close(\*WRITE, \*READ, \*ERROR);