post_install() {
  # Check if the isolate group exists (if not, create it)
  if ! getent group isolate >/dev/null; then
    groupadd isolate

    echo
    echo ">>> If you want to run the isolate command without sudo, you should add"
    echo ">>> yourself to the isolate group, like this:"
    echo ">>>   # sudo usermod -a -G isolate <your user>"
    echo ">>> However, keep in mind that:"
    echo ">>>   1. You will need to logout, in order to make the change effective"
    echo ">>>   2. No untrusted user should ever be allowed in the isolate group,"
    echo ">>>      as they may exploit the isolate command to gain root access"
    echo
  fi

  # Allow only users in the "isolate" group to run this without sudo
  chown root:isolate /usr/bin/isolate

  # Restore setuid bit
  chmod u+s /usr/bin/isolate
}

post_upgrade() {
  post_install $1
}

post_remove() {
  groupdel isolate
}