post_install() {
  if [ ! `grep osiris etc/group` ]; then
    groupadd -g 18 osiris &>/dev/null;
  fi

  id osiris &>/dev/null || \
    useradd -u 18 -g osiris -d /var/lib/osiris -s /bin/false osiris
}

post_upgrade() {
  post_install $1
}

pre_remove() {
  userdel osiris &> /dev/null
  groupdel osiris &> /dev/null
}