Perl wrapper to run process as different user and group

gistfile1.pl

#!/usr/bin/perl -w
use strict;
use diagnostics;

my $uid = (getpwnam("saned"))[2];
my $gid = (getgrnam("scanner"))[2];

$( = $) = "$gid $gid";
$< = $> = "$uid";
if (
	($< ne "$uid") or
	($> ne "$uid") or
	($( ne "$gid $gid") or
	($) ne "$gid $gid")
){
	die "Failed to drop privileges to: $uid/$gid. Aborting.\n";
}

exec ('/usr/bin/id') or die "Couldn't exec!\n";