post_install() {
  if [ -z "`getent group clamav`" ]; then
    groupadd -g 64 clamav
  fi
  if [ -z "`getent passwd clamav`" ]; then
    useradd -u 64 -g clamav -c "Clam AntiVirus" -d /dev/null -s /bin/false clamav
  fi
}

post_upgrade() {
  post_install $1
}

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

op=$1
shift

$op $*