pre_upgrade() {
  echo Removing old files ...
  pre_remove
}

post_upgrade() {
  echo Extracting upgrade files ...
  post_install
}

post_install() {
  cd /opt/psiral
  tar zxf psiral-bin.tar.gz
  rm -f psiral-bin.tar.gz
}

pre_remove() {
  cd /opt/psiral
  rm -f Psiral
  rm -f *.dat
  rm -f *.pak
  rm -f *.so
  if [ -d locales ]; then
    rm -f locales/*
    rmdir locales
  fi
}