PREIN

/bin/sh

getent group bucky >/dev/null || groupadd -r bucky
getent passwd bucky >/dev/null || \
    useradd -r -g bucky -d / \
    -s /sbin/nologin -c "Bucky daemon" bucky

POSTUN

/bin/sh

if [ $1 = 0 ]; then
  getent passwd bucky >/dev/null && \
      userdel -r bucky 2>/dev/null
fi