$UID = $new_uid;
$GID = $new_gid;
$EUID = $new_uid;
$EGID = "$new_gid $new_gid";

##</code><code>##

UID: '1001'
GID: '100 33'
EUID: '1001'
EGID: '100 33'

##</code><code>##

($UID, $GID) = ($new_uid, $new_gid);
($EUID, $EGID) = ($new_uid, "$new_gid $new_gid");

##</code><code>##

UID: '1001'
GID: '100 100'
EUID: '1001'
EGID: '100 100'